Multilayer, heat-shrinkable film comprising a plurality of microlayers

ABSTRACT

A multilayer, heat-shrinkable film generally includes at least one bulk layer and a microlayer section comprising at least 10 microlayers, each of which has a thickness ranging from about 0.001 to 0.015 mil. The ratio of the thickness of any of the microlayers to the thickness of the bulk layer is at least about 1:2. The film has a total free shrink (ASTM D2732-03) of at least about 10% at 200° F.

This application is a continuation of U.S. patent application Ser. No.13/290,432, filed Nov. 7, 2011, now U.S. Pat. No. 8,241,736, which is acontinuation of U.S. patent application Ser. No. 13/175,256, filed Jul.1, 2011, now U.S. Pat. No. 8,080,310, which is a divisional of U.S.patent application Ser. No. 12/381,135, filed Mar. 6, 2009, now U.S.Pat. No. 8,012,572, the disclosures of which are hereby incorporatedherein by reference thereto.

BACKGROUND OF THE INVENTION

The present invention relates to packaging materials of a type employingflexible, polymeric, heat-shrinkable films. More specifically, theinvention pertains to multilayer, heat-shrinkable films comprising aplurality of microlayers.

One distinguishing feature of a heat-shrinkable film is the film'sability, upon exposure to a certain temperature, to shrink or, ifrestrained from shrinking, to generate shrink tension within the film.

The manufacture of shrink films is well known in the art, and may begenerally accomplished by extrusion (single layer films) or coextrusion(multi-layer films) of thermoplastic polymeric materials which have beenheated to their flow or melting point from an extrusion or coextrusiondie, e.g., either in tubular or planer (sheet) form. After apost-extrusion quench to cool, e.g., by water immersion, the relativelythick “tape” extrudate is then reheated to a temperature within itsorientation temperature range and stretched to orient or align thecrystallites and/or molecules of the material. The orientationtemperature range for a given material or materials will vary with thedifferent resinous polymers and/or blends thereof which comprise thematerial. However, the orientation temperature range for a giventhermoplastic material may generally be stated to be below thecrystalline melting point of the material but above the second ordertransition temperature (sometimes referred to as the glass transitionpoint) thereof. Within this temperature range, a film may effectively beoriented.

The terms “orientation” or “oriented” are used herein to generallydescribe the process step and resultant product characteristics obtainedby stretching and immediately cooling a thermoplastic polymeric materialwhich has been heated to a temperature within its orientationtemperature range so as to revise the molecular configuration of thematerial by physical alignment of the crystallites and/or molecules ofthe material to impart certain mechanical properties to the film suchas, for example, shrink tension (ASTM D-2838) and heat-shrinkability(expressed quantitatively as “free shrink” per ASTM D-2732). When thestretching force is applied in one direction, uniaxial orientationresults. When the stretching force is applied in two directions, biaxialorientation results. The term oriented is also used hereininterchangeably with the term “heat-shrinkable,” with these termsdesignating a material which has been stretched and set by cooling whilesubstantially retaining its stretched dimensions. An oriented (i.e.,heat-shrinkable) material will tend to return to its originalunstretched (unextended) dimensions when heated to an appropriateelevated temperature.

Returning to the basic process for manufacturing the film as discussedabove, it can be seen that the film, once extruded (or coextruded if itis a multi-layer film) and initially cooled, e.g., by water quenching,is then reheated to within its orientation temperature range andoriented by stretching. The stretching to orient may be accomplished inmany ways such as, for example, by the “blown bubble” or “tenterframing” techniques. These processes are well known to those in the artand refer to orientation procedures whereby the material is stretched inthe cross or transverse direction (TD) and/or in the longitudinal ormachine direction (MD). After being stretched, the film is quicklyquenched while substantially retaining its stretched dimensions torapidly cool the film and thus set or lock-in the oriented (aligned)molecular configuration.

The degree of stretching controls the degree or amount of orientationpresent in a given film. Greater degrees of orientation are generallyevidenced by, for example, increased values of shrink tension and freeshrink. That is, generally speaking, for films manufactured from thesame material under otherwise similar conditions, those films which havebeen stretched, e.g. oriented, to a greater extent will exhibit largervalues for free shrink and shrink tension.

In many cases, after being extruded but prior to being stretch-oriented,the film is irradiated, normally with electron beams, to inducecross-linking between the polymer chains that make up the film.

After setting the stretch-oriented molecular configuration, the film maythen be stored in rolls and utilized to tightly package a wide varietyof items. In this regard, the product to be packaged may first beenclosed in the heat shrinkable material by heat sealing the shrink filmto itself to form a pouch or bag, then inserting the product therein andclosing the bag or pouch by heat sealing or other appropriate means suchas, for example, clipping. If the material was manufactured by the“blown bubble” technique, the material may still be in tubular form orit may have been slit and opened up to form a sheet of film material.Alternatively, a sheet of the material may be utilized to over-wrap theproduct, which may be in a tray.

After the enclosure step, the enclosed product is subjected to elevatedtemperatures by, for example, passing the enclosed product through a hotair or hot water tunnel. This causes the enclosing film to shrink aroundthe product to produce a tight wrapping that closely conforms to thecontour of the product.

The above general outline for the manufacturing and use ofheat-shrinkable films is not intended to be all inclusive since suchprocesses are well known to those of ordinary skill in the art. Forexample, see U.S. Pat. Nos. 3,022,543 and 4,551,380, the entiredisclosures of which are hereby incorporated herein by reference.

While shrink films have been made and used in the foregoing manner for anumber of years, there remains a need for improvement. Specifically,there is a need to reduce the amount of polymer used to make shrinkfilms, while maintaining in such films the physical properties that arenecessary for the films to perform their intended function asheat-shrinkable packaging films. Such a reduction in polymer usage wouldbeneficially reduce the utilization of petroleum and natural gasresources, from which polymers employed in most shrink films arederived, and would also reduce the amount of material contributed tolandfills by discarded shrink films. Moreover, a reduction in the usageof polymers for shrink films would beneficially reduce the materialcosts for such films.

SUMMARY OF THE INVENTION

The foregoing needs and challenges are met by the present invention,which provides a multilayer, heat-shrinkable film, comprising at leastone bulk layer and a microlayer section comprising a plurality ofmicrolayers. Each of the microlayers and the bulk layer have athickness, and the ratio of the thickness of any of the microlayers tothe thickness of the bulk layer ranges from about 1:2 to about 1:40.

In some embodiments, the heat-shrinkable film has a thickness of lessthan about 0.7 mil and an Elmendorf Tear value (ASTM D1922-06a) of atleast 10 grams, as measured in at least one direction along a length orwidth dimension of the film.

In other embodiments, at least one of the microlayers comprises a blendof two more polymers and has a composition that is different from atleast one other microlayer. Advantageously, regardless of thickness,such heat-shrinkable film will exhibit an Elmendorf Tear value (ASTMD1922-06a) of at least about 30 grams/mil, as measured in at least onedirection along a length or width dimension of the film.

The foregoing embodiments represent significant improvements inElmendorf Tear vs. conventional shrink films, i.e., those that do nothave a microlayer section. Because of such improvements, shrink filmsmay be made in accordance with the present invention that have lessthickness, and therefore less polymer usage, than conventional shrinkfilms, while still maintaining the properties necessary to perform theirintended function.

In many embodiments, shrink films in accordance with the presentinvention have a total free shrink (ASTM D2732-03) of at least about 10%at 200° F.

In some embodiments, the microlayer section may comprise a repeatingsequence of layers represented by the structure:A/B,wherein,

A represents a microlayer comprising one or more polymers;

B represents a microlayer comprising a blend of two or more polymers;and

A has a composition that is different from that of B.

One method of making the multilayer, heat-shrinkable films as describedabove comprises:

a. extruding a bulk layer;

b. coextruding a plurality of microlayers to form a microlayer section;

c. merging the bulk layer and the microlayer section to form amultilayer film; and

d. stretch-orienting the multilayer film under conditions that impartheat-shrinkability to the film;

wherein, each of the microlayers and the bulk layer have a thickness,the ratio of the thickness of any of the microlayers to the thickness ofthe bulk layer ranging from about 1:2 to about 1:40; and

wherein, the film has a total free shrink (ASTM D2732-03) of at leastabout 10% at 200° F.

Another method of making multilayer, heat-shrinkable films in accordancewith the present invention comprises:

a. directing a first polymer through a distribution plate and onto aprimary forming stem, the distribution plate having a fluid inlet and afluid outlet, the fluid outlet from the plate being in fluidcommunication with the primary forming stem and structured such that thefirst polymer is deposited onto the primary forming stem as a bulklayer;

b. directing at least a second polymer through a microlayer assembly,the microlayer assembly comprising a plurality of microlayerdistribution plates and a microlayer forming stem, each of themicrolayer plates having a fluid inlet and a fluid outlet, the fluidoutlet from each of the microlayer plates being in fluid communicationwith the microlayer forming stem and structured to deposit a microlayerof polymer onto the microlayer forming stem, the microlayer plates beingarranged to provide a predetermined order in which the microlayers aredeposited onto the microlayer forming stem, thereby forming asubstantially unified, microlayered fluid mass;

c. directing the microlayered fluid mass from the microlayer formingstem and onto the primary forming stem to merge the microlayered fluidmass with the bulk layer, thereby forming a multilayer film; and

d. stretch-orienting the multilayer film under conditions that impartheat-shrinkability to the film.

These and other aspects and features of the invention may be betterunderstood with reference to the following description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a system 10 in accordance with the presentinvention for coextruding a multilayer film;

FIG. 2 is a cross-sectional view of the die 12 shown in FIG. 1;

FIG. 3 is a plan view one of the microlayer plates 48 in die 12;

FIG. 4 is a cross-sectional view of the microlayer plate 48 shown inFIG. 3;

FIG. 5 is a magnified, cross-sectional view of die 12, showing thecombined flows from the microlayer plates 48 and distribution plates 32;

FIG. 6 is a cross-sectional view of a multilayer, heat-shrinkable film,which may be produced from die 12 as shown in FIG. 2;

FIG. 7 is a graph showing Elemendorf tear-resistance strength for eachof the films of Examples 1-23; and

FIG. 8 is a cross-sectional view of an alternative multilayer,heat-shrinkable film, which may also be produced from die 12 as shown inFIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 schematically illustrates a system 10 in accordance with thepresent invention for coextruding a plurality of fluid layers. Suchfluid layers typically comprise fluidized polymeric layers, which are ina fluid state by virtue of being molten, i.e., maintained at atemperature above the melting point of the polymer(s) used in eachlayer.

System 10 generally includes a die 12 and one or more extruders 14 a and14 b in fluid communication with the die 12 to supply one or morefluidized polymers to the die. As is conventional, the polymericmaterials may be supplied to the extruders 14 a, b in the solid-state,e.g., in the form of pellets or flakes, via respective hoppers 16 a, b.Extruders 14 a, b are maintained at a temperature sufficient to convertthe solid-state polymer to a molten state, and internal screws withinthe extruders (not shown) move the molten polymer into and through die12 via respective pipes 18 a, b. As will be explained in further detailbelow, within die 12, the molten polymer is converted into thin filmlayers, and each of the layers are superimposed, combined together, andexpelled from the die at discharge end 20, i.e., “coextruded,” to form atubular, multilayer film 22. Upon emergence from the die 12 at dischargeend 20, the tubular, multilayer film 22 is exposed to ambient air or asimilar environment having a temperature sufficiently low to cause themolten polymer from which the film is formed to transition from a liquidstate to a solid state. Additional cooling/quenching of the film may beachieved by providing a liquid quench bath (not shown), and thendirecting the film through such bath.

The solidified tubular film 22 is then collapsed by a convergence device24, e.g., a V-shaped guide as shown, which may contain an array ofrollers to facilitate the passage of film 22 therethrough. A pair ofcounter-rotating drive rollers 25 a, b may be employed as shown to pullthe film 22 through the convergence device 24. The resultant collapsedtubular film 22 may then be wound into a roll 26 by a film windingdevice 28 as shown. The film 22 on roll 26 may subsequently be unwoundfor use, e.g., for packaging, or for further processing, e.g.,stretch-orientation, irradiation, or other conventional film-processingtechniques, which are used to impart desired properties as necessary forthe intended end-use applications for the film.

Referring now to FIG. 2, die 12 will be described in further detail. Asnoted above, die 12 is adapted to coextrude a plurality of fluid layers,and generally includes a primary forming stem 30, one or moredistribution plates 32, and a microlayer assembly 34. In the presentlyillustrated die, five distribution plates 32 are included, asindividually indicated by the reference numerals 32 a-e. A greater orlesser number of distribution plates 32 may be included as desired. Thenumber of distribution plates in die 12 may range, e.g., from one totwenty, or even more then twenty if desired.

Each of the distribution plates 32 has a fluid inlet 36 and a fluidoutlet 38 (the fluid inlet is only shown in plate 32 a). The fluidoutlet 38 from each of the distribution plates 32 is in fluidcommunication with the primary forming stem 30, and also is structuredto deposit a layer of fluid onto the primary forming stem. Thedistribution plates 32 may be constructed as described in U.S. Pat. No.5,076,776, the entire disclosure of which is hereby incorporated hereinby reference thereto. As described in the '776 patent, the distributionplates 32 may have one or more spiral-shaped fluid-flow channels 40 todirect fluid from the fluid inlet 36 and onto the primary forming stem30 via the fluid outlet 38. As the fluid proceeds along the channel 40,the channel becomes progressively shallower such that the fluid isforced to assume a progressively thinner profile. The fluid outlet 38generally provides a relatively narrow fluid-flow passage such that thefluid flowing out of the plate has a final desired thicknesscorresponding to the thickness of the fluid outlet 38. Other channelconfigurations may also be employed, e.g., a toroid-shaped channel; anasymmetrical toroid, e.g., as disclosed in U.S. Pat. No. 4,832,589; aheart-shaped channel; a helical-shaped channel, e.g., on aconical-shaped plate as disclosed in U.S. Pat. No. 6,409,953, etc. Thechannel(s) may have a semi-circular or semi-oval cross-section as shown,or may have a fuller shape, such as an oval or circular cross-sectionalshape.

Distribution plates 32 may have a generally annular shape such that thefluid outlet 38 forms a generally ring-like structure, which forcesfluid flowing through the plate to assume a ring-like form. Suchring-like structure of fluid outlet 38, in combination with itsproximity to the primary forming stem 30, causes the fluid flowingthrough the plate 32 to assume a cylindrical shape as the fluid isdeposited onto the stem 30. Each flow of fluid from each of thedistribution plates 32 thus forms a distinct cylindrical “bulk” layer onthe primary forming stem 30, i.e. layers that have greater bulk, e.g.,thickness, than those formed from the microlayer assembly 34 (asdescribed below).

The fluid outlets 38 of the distribution plates 32 are spaced from theprimary forming stem 30 to form an annular passage 42. The extent ofsuch spacing is sufficient to accommodate the volume of the concentricfluid layers flowing along the forming stem 30.

The order in which the distribution plates 32 are arranged in die 12determines the order in which the fluidized bulk layers are depositedonto the primary forming stem 30. For example, if all five distributionplates 32 a-e are supplied with fluid, fluid from plate 32 a will be thefirst to be deposited onto primary forming stem 30 such that such fluidwill be in direct contact with the stem 30. The next bulk layer to bedeposited onto the forming stem would be from distribution plate 32 b.This layer will be deposited onto the fluid layer from plate 32 a. Next,fluid from plate 32 c will be deposited on top of the bulk layer fromplate 32 b. If microlayer assembly 34 were not present in the die, thenext bulk layer to be deposited would be from distribution plate 32 d,which would be layered on top of the bulk layer from plate 32 c.Finally, the last and, therefore, outermost bulk layer to be depositedwould be from plate 32 e. In this example (again, ignoring themicrolayer assembly 34), the resultant tubular film 22 that would emergefrom the die would have five distinct bulk layers, which would bearranged as five concentric cylinders bonded together.

Accordingly, it may be appreciated that the fluid layers from thedistribution plates 32 are deposited onto the primary forming stem 30either directly (first layer to be deposited, e.g., from distributionplate 32 a) or indirectly (second and subsequent layers, e.g., fromplates 32 b-e).

As noted above, the tubular, multilayer film 22 emerges from die 12 atdischarge end 20. The discharge end 20 may thus include an annulardischarge opening 44 to allow the passage of the tubular film 22 out ofthe die. The die structure at discharge end 20 that forms such annularopening is commonly referred to as a “die lip.” As illustrated, thediameter of the annular discharge opening 44 may be greater than that ofthe annular passage 42, e.g., to increase the diameter of the tubularfilm 22 to a desired extent. This has the effect of decreasing thethickness of each of the concentric layers that make up the tubular film22, i.e., relative to the thickness of such layers during theirresidence time within the annular passage 42. Alternatively, thediameter of the annular discharge opening 44 may be smaller than that ofthe annular passage 42.

Microlayer assembly 34 generally comprises a microlayer forming stem 46and a plurality of microlayer distribution plates 48. In the presentlyillustrated embodiment, fifteen microlayer distribution plates 48 a-oare shown. A greater or lesser number of microlayer distribution plates48 may be included as desired. The number of microlayer distributionplates 48 in microlayer assembly 34 may range, e.g., from one to fifty,or even more then fifty if desired. In many embodiments of the presentinvention, the number of microlayer distribution plates 48 in microlayerassembly 34 will be at least about 5, e.g., 10, 15, 20, 25, 30, 35, 40,45, 50, etc., or any number of plates in between the foregoing numbers.

Each of the microlayer plates 48 has a fluid inlet 50 and a fluid outlet52. The fluid outlet 52 from each of the microlayer plates 48 is influid communication with microlayer forming stem 46, and is structuredto deposit a microlayer of fluid onto the microlayer forming stem.Similar to the distribution plates 32, the microlayer plates 48 may alsobe constructed as described in the above-incorporated U.S. Pat. No.5,076,776.

For example, as shown in FIG. 3, the microlayer plates 48 may have aspiral-shaped fluid-flow channel 54, which is supplied with fluid viafluid inlet 50. Alternatively, two or more fluid-flow channels may beemployed in plate 48, which may be fed from separate fluid inlets or asingle fluid inlet. Other channel configurations may also be employed,e.g., a toroid-shaped channel; an asymmetrical toroid, e.g., asdisclosed in U.S. Pat. No. 4,832,589; a heart-shaped channel; ahelical-shaped channel, e.g., on a conical-shaped plate as disclosed inU.S. Pat. No. 6,409,953; etc. The channel(s) may have a semi-circular orsemi-oval cross-section as shown, or may have a fuller shape, such as anoval or circular cross-sectional shape.

Regardless of the particular configuration or pattern that is selectedfor the flow channel(s) 54, its function is to connect the fluidinlet(s) 50 with the fluid outlet 52 in such a manner that the flow offluid through the microlayer assembly 34 is converted from a generallystream-like, axial flow to a generally film-like, convergent radial flowtowards the microlayer forming stem 46. Microlayer plate 48 as shown inFIG. 3 may accomplish this in two ways. First, the channel 54 spiralsinwards towards the center of the plate, and thus directs fluid from thefluid inlet 50, located near the periphery of the plate, towards thefluid outlet 52, which is located near the center of the plate.Secondly, the channel 54 may be fashioned with a progressively shallowerdepth as the channel approaches the fluid outlet 52. This has the effectof causing some of the fluid flowing through the channel 54 to overflowthe channel and proceed radially-inward toward the fluid outlet 52 in arelatively flat, film-like flow. Such radial-inward flow may occur inoverflow regions 53, which may be located between the spaced-apartspiral sections of channel 54. As shown in FIG. 4, the overflow regions53 may be formed as recessed sections in plate 48, i.e., recessedrelative to the thicker, non-recessed region 55 at the periphery of theplate. As shown in FIG. 3, overflow regions 53 may begin at step-down 57and, e.g., spiral inwards towards fluid outlet 52 between the spirals ofchannel 54. The non-recessed, peripheral region 55 abuts against theplate or other structure above the plate, e.g., as shown in FIGS. 2 and5, and thus prevents fluid from flowing outside the periphery of theplate. In this manner, the non-recessed, peripheral region 55 forcesfluid entering the plate to flow radially inward toward fluid outlet 52.Step-down 57 thus represents a line or zone of demarcation between the‘no-flow’ peripheral region 55 and the ‘flow’ regions 53 and 54. Thefluid that remains in the channel 54 and reaches the end 56 of thechannel flows directly into the fluid outlet 52.

The fluid outlet 52 generally provides a relatively narrow fluid-flowpassage and generally determines the thickness of the microlayer flowingout of the microlayer plate 48. The thickness of the fluid outlet 52,and therefore the thickness of the microlayer flowing therethrough, maybe determined, e.g., by the spacing between the plate surface at outlet52 and the bottom of the plate or other structure (e.g., manifold 76 or78) immediately above the plate surface at outlet 52.

With continuing reference to FIGS. 2-3, each of the microlayerdistribution plates 48 may have an orifice 58 extending through theplate. The orifice 58 may be located substantially in the center of eachmicrolayer plate 48, with the fluid outlet 52 of each plate positionedadjacent to such orifice 58. In this manner, the microlayer forming stem46 may extend through the orifice 58 of each of the microlayerdistribution plates 48. With such a configuration, the microlayerdistribution plates 48 may have a generally annular shape such that thefluid outlet 52 forms a generally ring-like structure, which forcesfluid flowing through the plate to exit the plate in aradially-convergent, ring-like flow pattern. Such ring-like structure offluid outlet 52, in combination with its proximity to the microlayerforming stem 46, causes the fluid exiting the microlayer plates 48 toassume a cylindrical shape as the fluid is deposited onto the microlayerstem 46. Each flow of fluid from each of the microlayer distributionplates 48 thus deposits a distinct cylindrical microlayer on themicrolayer forming stem 46.

The microlayer plates 48 may be arranged to provide a predeterminedorder in which the microlayers are deposited onto the microlayer formingstem 46. For example, if all fifteen microlayer distribution plates 48a-o are supplied with fluid, a microlayer of fluid from plate 48 a willbe the first to be deposited onto microlayer forming stem 46 such thatsuch microlayer will be in direct contact with the stem 46. The nextmicrolayer to be deposited onto the forming stem would be frommicrolayer plate 48 b. This microlayer will be deposited onto themicrolayer from plate 48 a. Next, fluid from microlayer plate 48 c willbe deposited on top of the microlayer from plate 48 b, etc. The lastand, therefore, outermost microlayer to be deposited is from plate 48 o.In this manner, the microlayers are deposited onto the microlayerforming stem 46 in the form of a substantially unified, microlayeredfluid mass 60 (see FIG. 5). In the present example, such microlayeredfluid mass 60 would comprise up to fifteen distinct microlayers (at thedownstream end of stem 46), arranged as fifteen concentric cylindricalmicrolayers bonded and flowing together in a predetermined order (basedon the ordering of the microlayer plates 48 a-o) on microlayer formingstem 46.

It may thus be appreciated that the fluid layers from the microlayerdistribution plates 48 are deposited onto the microlayer forming stem 46either directly (the first layer to be deposited, e.g., from microlayerplate 48 a) or indirectly (the second and subsequent layers, e.g., frommicrolayer plates 48 b-o). The orifices 58 in each of the microlayerplates 48 are large enough in diameter to space the fluid outlets 52 ofthe microlayer plates 48 sufficiently from the microlayer forming stem46 to form an annular passage 62 for the microlayers (FIG. 2). Theextent of such spacing is preferably sufficient to accommodate thevolume of the concentric microlayers flowing along the microlayer stem46.

In accordance with the present invention, microlayer forming stem 46 isin fluid communication with primary forming stem 30 such that themicrolayered fluid mass 60 flows from the microlayer forming stem 46 andonto the primary forming stem 30. This may be seen in FIG. 5, whereinmicrolayered fluid mass 60 from microlayer assembly 34 is shown flowingfrom microlayer forming stem 46 and onto primary forming stem 30. Fluidcommunication between the microlayer stem 46 and primary stem 30 may beachieved by including in die 12 an annular transfer gap 64 between theannular passage 62 for the microlayer stem 46 and the annular passage 42for the primary stem 30 (see also FIG. 2). Such transfer gap 64 allowsthe microlayered fluid mass 60 to flow out of the annular passage 62 andinto the annular passage 42 for the primary forming stem 30. In thismanner, the microlayers from microlayer plates 48 are introduced as aunified mass into the generally larger volumetric flow of the thickerfluid layers from the distribution plates 32.

The microlayer forming stem 46 allows the microlayers from themicrolayer plates 48 to assemble into the microlayered fluid mass 60 inrelative calm, i.e., without being subjected to the more powerful sheerforces of the thicker bulk layers flowing from the distribution plates32. As the microlayers assemble into the unified fluid mass 60 on stem46, the interfacial flow instabilities created by the merger of eachlayer onto the fluid mass 60 are minimized because all the microlayershave a similar degree of thickness, i.e., relative to the larger degreeof thickness of the bulk fluid layers from distribution plates 32. Whenfully assembled, the microlayered fluid mass 60 enters the flow of thethicker bulk layers from distribution plates 32 on primary stem 30 witha mass flow rate that more closely approximates that of such thickerlayers, thereby increasing the ability of the microlayers in fluid mass60 to retain their physical integrity and independent physicalproperties.

As shown in FIG. 2, primary forming stem 30 and microlayer forming stem46 may be substantially coaxially aligned with one another in die 12,e.g., with the microlayer forming stem 46 being external to the primaryforming stem 30. This construction provides a relatively compactconfiguration for die 12, which can be highly advantageous in view ofthe stringent space constraints that exist in the operating environmentof many commercial coextrusion systems.

Such construction also allows die 12 to be set up in a variety ofdifferent configurations to produce a coextruded film having a desiredcombination of bulk layers and microlayers. For example, one or moredistribution plates 32 may be located upstream of the microlayerassembly 34. In this embodiment, fluidized bulk layers from suchupstream distribution plates are deposited onto primary forming stem 30prior to the deposition of the microlayered fluid mass 60 onto theprimary stem 30. With reference to FIG. 2, it may be seen thatdistribution plates 32 a-c are located upstream of microlayer assembly34 in die 12. Bulk fluid layers 65 from such upstream distributionplates 32 a-c are thus interposed between the microlayered fluid mass 60and the primary forming stem 30 (see FIG. 5).

Alternatively, the microlayer assembly 34 may be located upstream of thedistribution plates 32, i.e., the distribution plates may be locateddownstream of the microlayer assembly 34 in this alternative embodiment.Thus, the microlayers from the microlayer assembly 34, i.e., themicrolayered fluid mass 60, will be deposited onto primary forming stem30 prior to the deposition thereon of the bulk fluid layers from thedownstream distribution plates 32. With reference to FIG. 2, it may beseen that microlayer assembly 34 is located upstream of distributionplates 32 d-e in die 12. As shown in FIG. 5, the microlayered fluid mass60 is thus interposed between the bulk fluid layer(s) 70 from suchdistribution plates 32 d-e and the primary forming stem 30.

As illustrated in FIG. 2, the microlayer assembly 34 may also bepositioned between one or more upstream distribution plates, e.g.,plates 32 a-c, and one or more downstream distribution plates, e.g.,plates 32 d-e. In this embodiment, fluid(s) from upstream plates 32 a-care deposited first onto primary stem 30, followed by the microlayeredfluid mass 60 from the microlayer assembly 34, and then further followedby fluid(s) from downstream plates 32 d-e. In the resultant multilayeredfilm, the microlayers from microlayer assembly 34 are sandwiched betweenthicker, bulk layers from both the upstream plates 32 a-c and thedownstream plates 32 d-e.

In many embodiments of the invention, most or all of the microlayerplates 48 have a thickness that is less than that of the distributionplates 32. Thus, for example, the distribution plates 32 may have athickness T₁ (see FIG. 5) ranging from about 0.5 to about 2 inches. Themicrolayer distribution plates 48 may have a thickness T₂ ranging fromabout 0.1 to about 0.5 inch. Such thickness ranges are not intended tobe limiting in any way, but only to illustrate typical examples. Alldistribution plates 32 will not necessarily have the same thickness, norwill all of the microlayer plates 48. For example, microlayer plate 48o, the most downstream of the microlayer plates in the assembly 34, maybe thicker than the other microlayer plates to accommodate a slopedcontact surface 66, which may be employed to facilitate the transfer ofmicrolayered fluid mass 60 through the annular gap 64 and onto theprimary forming stem 30.

As also shown in FIG. 5, each of the microlayers flowing out of theplates 48 has a thickness “M” corresponding to the thickness of thefluid outlet 52 from which each microlayer emerges. The microlayersflowing from the microlayer plates 48 are schematically represented inFIG. 5 by the phantom arrows 68.

Similarly, each of the relatively thick bulk layers flowing out of theplates 32 has a thickness “D” corresponding to the thickness of thefluid outlet 38 from which each such layer emerges (see FIG. 5). Thethicker/bulk layers flowing from the distribution plates 32 areschematically represented in FIG. 5 by the phantom arrows 70.

Generally, the thickness M of the microlayers will be less than thethickness D of the bulk layers from the distribution plates 32. Thethinner that such microlayers are relative to the bulk layers from thedistribution plates 32, the more of such microlayers that can beincluded in a multilayer film, for a given overall film thickness.Microlayer thickness M from each microlayer plate 48 will generallyrange from about 1-20 mils (1 mil=0.001 inch). Thickness D from eachdistribution plate 32 will generally range from about 20-100 mils.

The ratio of M:D may range from about 1:1 to about 1:8. Thickness M maybe the same or different among the microlayers 68 flowing frommicrolayer plates 48 to achieve a desired distribution of layerthicknesses in the microlayer section of the resultant film. Similarly,thickness D may be the same or different among the thicker bulk layers70 flowing from the distribution plates 32 to achieve a desireddistribution of layer thicknesses in the bulk-layer section(s) of theresultant film.

The layer thicknesses M and D will typically change as the fluid flowsdownstream through the die, e.g., if the melt tube is expanded atannular discharge opening 44 as shown in FIG. 2, and/or upon furtherdownstream processing of the tubular film, e.g., by stretching,orienting, or otherwise expanding the tube to achieve a final desiredfilm thickness and/or to impart desired properties into the film. Theflow rate of fluids through the plates will also have an effect on thefinal downstream thicknesses of the corresponding film layers.

As described above, the distribution plates 32 and microlayer plates 48preferably have an annular configuration, such that primary forming stem30 and microlayer stem 46 pass through the center of the plates toreceive fluid that is directed into the plates. The fluid may besupplied from extruders, such as extruders 14 a, b. The fluid may bedirected into the die 12 via vertical supply passages 72, which receivefluid from feed pipes 18, and direct such fluid into the die plates 32and 48. For this purpose, the plates may have one or more through-holes74, e.g., near the periphery of the plate as shown in FIG. 3, which maybe aligned to provide the vertical passages 72 through which fluid maybe directed to one or more downstream plates.

Although three through-holes 74 are shown in FIG. 3, a greater or lessernumber may be employed as necessary, e.g., depending upon the number ofextruders that are employed. In general, one supply passage 72 may beused for each extruder 14 that supplies fluid to die 12. The extruders14 may be arrayed around the circumference of the die, e.g., like thespokes of a wheel feeding into a hub, wherein the die is located at thehub position.

With reference to FIG. 1, die 12 may include a primary manifold 76 toreceive the flow of fluid from the extruders 14 via feed pipes 18, andthen direct such fluid into a designated vertical supply passage 72, inorder to deliver the fluid to the intended distribution plate(s) 32and/or microlayer plate(s) 48. The microlayer assembly 34 may optionallyinclude a microlayer manifold 78 to receive fluid directly from one ormore additional extruders 80 via feed pipe 82 (shown in phantom in FIG.1).

In the example illustrated in FIGS. 1-2, extruder 14 b delivers a fluid,e.g., a first molten polymer, directly to the fluid inlet 36 ofdistribution plate 32 a via pipe 18 b and primary manifold 76. In thepresently illustrated embodiment, distribution plate 32 a receives allof the output from extruder 14 b, i.e., such that the remaining platesand microlayer plates in the die 12 are supplied, if at all, from otherextruders. Alternatively, the fluid inlet 36 of distribution plate 32 amay be configured to contain an outlet port to allow a portion of thesupplied fluid to pass through to one or more additional plates, e.g.,distribution plates 32 and/or microlayer plates 48, positioneddownstream of distribution plate 32 a.

For example, as shown in FIGS. 3-4 with respect to the illustratedmicrolayer plate 48, an outlet port 84 may be formed in the base of thefluid inlet 50 of the plate. Such outlet port 84 allows the flow offluid delivered to plate 48 to be split: some of the fluid flows intochannel 54 while the remainder passes through the plate for delivery toone or more additional downstream plates 48 and/or 32. A similar outletport can be included in the base of the fluid inlet 36 of a distributionplate 32. Delivery of fluid passing through the outlet port 84 (orthrough a similar outlet port in a distribution plate 32) may beeffected via a through-hole 74 in an adjacent plate (see FIG. 5), or viaother means, e.g., a lateral-flow supply plate, to direct the fluid inan axial, radial, and/or tangential direction through die 12 asnecessary to reach its intended destination.

Distribution plates 32 b-c are being supplied with fluid via extruder(s)and supply pipe(s) and/or through-holes that are not shown in FIG. 2.The bulk fluid flow along primary forming stem 30 from distributionplates 32 a-c is shown in FIG. 5, as indicated by reference numeral 65.

As shown in FIGS. 1-2, microlayer assembly 34 is being supplied withfluid by extruders 14 a and 80. Specifically, microlayer plates 48 a, c,e, g, i, k, m, and o are supplied by extruder 14 a via supply pipe 18 aand vertical pipe and/or passage 72. Microlayer plates 48 b, d, f, h, j,l, and n are supplied with fluid by extruder 80 via feed pipe 82 and avertical supply passage 86. In the illustrated embodiment, verticalpassage 86 originates in microlayer manifold 78 and delivers fluid onlywithin the microlayer assembly 34. In contrast, vertical passage 72originates in manifold 76, extends through distribution plates 32 a-c(via aligned through-holes 74 in such plates), then further extendsthrough manifold 78 via manifold passage 79 before finally arriving atmicrolayer plate 48 a.

Fluid from extruder 14 a and vertical passage 72 enters microlayer plate48 a at fluid inlet 50. Some of the fluid passes from inlet 50 and intochannel 54 (for eventual deposition on microlayer stem 46 as the firstmicrolayer to be deposited on stem 46), while the remainder of the fluidpasses through plate 48 a via outlet port 84. Microlayer plate 48 b maybe oriented, i.e., rotated, such that a through-hole 74 is positionedbeneath the outlet port 84 of microlayer plate 48 a so that the fluidflowing out of the outlet port 84 flows through the microlayer plate 48b, and not into the channel 54 thereof. Microlayer plate 48 c may bepositioned such that the fluid inlet 50 thereof is in the same locationas that of microlayer plate 48 a so that fluid flowing out ofthrough-hole 74 of microlayer plate 48 b flows into the inlet 50 ofplate 48 c. Some of this fluid flows into the channel 54 of plate 48 cwhile some of the fluid passes through the plate via outlet port 84,passes through a through-hole 74 in the next plate 48 d, and is receivedby fluid inlet 50 of the next microlayer plate 48 e, where some of thefluid flows into channel 54 and some passes out of the plate via outletport 84. Fluid from extruder 14 a continues to be distributed toremaining plates 48 g, i, k, and m in this manner, except for microlayerplate 48 o, which has no outlet port 84 so that fluid does not passthrough plate 48 o, except via channel 54 and fluid outlet 52.

In a similar manner, fluid from extruder 80 and vertical passage 86passes through microlayer plate 48 a via a through-hole 74 and thenenters microlayer plate 48 b at fluid inlet 50 thereof. Some of thisfluid flows through the channel 54 and exits the plate at outlet 52, tobecome the second microlayer to be deposited onto microlayer stem 46 (ontop of the microlayer from plate 48 a), while the remainder of the fluidpasses through the plate via an outlet port 84. Such fluid passesthrough microlayer plate 48 c via a through-hole 74, and is delivered toplate 48 d via appropriate alignment of its inlet 50 with thethrough-hole 74 of plate 48 c. This fluid-distribution process maycontinue for plates 48 f, h, j, and l, until the fluid reaches plate 48n, which has no outlet port 84 such that fluid does not pass throughthis plate except via its fluid outlet 52.

In this manner, a series of microlayers comprising alternating fluidsfrom extruders 14 a and 80 may be formed on microlayer stem 46. Forexample, if extruder 14 a supplied EVOH and extruder 80 supplied PA6,the resultant microlayered fluid mass 60 would have the structure:EVOH/PA6/EVOH/PA6/EVOH/PA6/EVOH/PA6/EVOH/PA6/EVOH/PA6/EVOH/PA6/EVOH

The fluids from extruders 14 a and 80 may be the same or different suchthat the resultant microlayers in microlayered fluid mass 60 may havethe same or a different composition. Only one extruder may be employedto supply fluid to the entire microlayer assembly 34, in which case allof the resultant microlayers will have the same composition.Alternatively, three or more extruders may be used to supply fluid tothe microlayer assembly 34, e.g., with each supplying a different fluid,e.g., polymer “a,” polymer “b,” and polymer “c,” respectively, such thatthree different microlayer compositions are formed in microlayered fluidmass 60, in any desired order, to achieve any desired layer-combination,e.g., abcabc; abbcabbc; abacabac; etc.

Similarly, the fluid(s) directed through the distribution plate(s) 32may be substantially the same as the fluid(s) directed through themicrolayer assembly 34. Alternatively, the fluid(s) directed through thedistribution plate(s) 32 may be different from the fluid(s) directedthrough the microlayer assembly. The resultant tubular film may havebulk layers and microlayers that have substantially the samecomposition. Alternatively, some of the bulk layers from distributionplates 32 may be the same as some or all of the microlayers frommicrolayer plates 48, while other bulk layers may be different from someor all of the microlayers.

In the illustrated example, the extruders and supply passages fordistribution plates 32 d-e are not shown. One or both of such plates maybe supplied from extruder 14 a, 14 b, and/or 80 by appropriatearrangement of vertical supply passages 72, 86, through-holes 74, and/oroutlet ports 84 of the upstream distribution plates 32 and/or microlayerplates 48. Alternatively, one or both distribution plates 32 d-e may notbe supplied at all, or may be supplied from a separate extruder, such asan extruder in fluid communication with primary manifold 76 and avertical supply passage 72 that extends through distribution plates 32a-c and microlayer assembly 34, e.g., via appropriate alignment of thethrough-holes 74 of plates 32 a-c and microlayer assembly 34 to create afluid transport passage through die 12, leading to fluid inlet 50 ofdistribution plate 32 d and/or 32 e.

If desired, one or more of the distribution plates 32 and/or microlayerplates 48 may be supplied with fluid directly from one or moreextruders, i.e., by directing fluid directly into the fluid inlet of theplate, e.g., from the side of the plate, without the fluid being firstrouted through one of manifolds 76 or 78 and/or without using a verticalsupply passage 72, 86. Such direct feed of one or more plates 32 and/or48 may be employed as an alternative or in addition to the use ofmanifolds and vertical supply passages as shown in FIG. 2.

The inventors have discovered that the system 10 is particularlyadvantageous when used to make a multilayer, heat-shrinkable film, i.e.,films that have been stretch-oriented such that they shrink uponexposure to heat. Surprisingly, it was discovered that the inclusion ofa plurality of microlayers in a heat-shrinkable film enabled thethickness, and therefore polymer usage, of such film to be reduced by upto 50%, yet still perform as well as an otherwise identical film havingtwice the thickness and twice the polymer usage. The plurality ofmicrolayers in the film results from the microlayered fluid mass 60 asdescribed above, which forms a microlayer section 60 in the film.

For example, heat-shrinkable films 94 in accordance with the presentinvention have at least one microlayer section 60, and one or more bulklayers, e.g., 90, 96, 98, and/or 100 (see, FIGS. 6 and 8), andpreferably have a total free shrink (ASTM D2732-03) of at least about10% at 200° F.

Such films may be formed from system 10 by directing a first polymer 88through extruder 14 b and distribution plate 32 a of die 12, and ontoprimary forming stem 30 such that the first polymer 88 is deposited ontoprimary forming stem 30 as a first bulk layer 90 (see FIGS. 1, 2 and 5).At least a second polymer 92 may be directed through extruder 14 a andmicrolayer assembly 34, e.g., via vertical passage 72, to formmicrolayered fluid mass 60 on microlayer forming stem 46. Themicrolayered fluid mass 60 is then directed from microlayer forming stem46 and onto primary forming stem 30. In this manner, the microlayeredfluid mass 60 is merged with first bulk layer 90 within die 12 (FIG. 5),thereby forming multilayer film 22 (FIG. 1) as a relatively thick “tape”extrudate, which comprises the bulk layer 90 and microlayer section 60as solidified film layers resulting from the fluid (molten) polymerlayer 90 and microlayered fluid mass 60 within die 12.

As the coextruded, tubular multilayer “tape” 22 emerges from thedischarge end 20 of die 12, it is quenched (e.g., via immersion inwater) and then stretch-oriented under conditions that impartheat-shrinkability to the film. Such conditions, as described above inthe Background section, may include reheating the multilayer “tape” to atemperature within its orientation temperature range, and thenstretching the tape, e.g., as a blown bubble, to orient (align) thecrystallites and/or molecules of the material, followed by quenching thefilm while substantially retaining its stretched dimensions to rapidlycool the film and thus lock-in the oriented molecular configuration. Inthis manner, the “tape” 22 is converted into a heat-shrinkable film 94,a cross-sectional view of which is shown in FIG. 6.

As may be appreciated, due to the stretching of the multilayer film or“tape” 22, the thickness of heat-shrinkable film 94 is significantlyless than that of the tape 22. For example, while the tape 22 may have athickness ranging from about 5 to about 50 mils, in many embodiments ofthe invention, the heat-shrinkable film 94 will have a thickness of lessthan 5 mils, such as 4 mils or less, 3 mils or less, 2 mils or less,etc. In some embodiments, the stretch-oriented shrink film 94 may berelatively very thin, i.e., less than 1 mil, e.g., less than about 0.9mil, such as less than about 0.8 mil, less than about 0.7 mil, or lessthan about 0.6 mil, such as about 0.59 mil or less, 0.58 mil or less,0.57 mil or less, 0.56 mil or less, 0.55 mil or less, 0.54 mil or less,0.53 mil or less, etc. Advantageously, microlayers 60 in accordance withthe present invention allow shrink film 94 to have an even lowerthickness of 0.5 mil or less, such as less than 0.45 mil, or less than0.40 mil, such as less than 0.39 mil, less than 0.38 mil, less than 0.37mil, less than 0.36 mil, less than 0.35 mil, less than 0.34 mil, lessthan 0.33 mil, less than 0.32 mil, or less than 0.31 mil, such about0.30 mil.

As shown in FIG. 5, first bulk layer 90 may be deposited onto primaryforming stem 30 prior to the deposition of the microlayered fluid mass60 onto the primary forming stem 30 such that the first layer 90 isinterposed between the microlayered fluid mass 60 and the primaryforming stem 30. If desired, a third polymer may be directed through asecond distribution plate, e.g., distribution plate 32 e (see FIG. 2;source of third polymer not shown). As shown in FIG. 5, the relativelythick flow 70 of such third polymer from distribution plate 32 e may bemerged with the microlayered fluid mass 60 to form a second bulk layer96 for the multilayer film 94. In this manner, the microlayer section 60may form a core for the multilayer film 94, with the first bulk layer 90forming a first outer layer for the multilayer film 94 and the secondbulk layer 96 forming a second outer layer therefor. Thus, in theembodiment illustrated in FIG. 6, heat-shrinkable film 94 comprisesmicrolayer section 60 positioned between the first and second bulk,outer layers 90, 96.

The second polymer 92 may be substantially the same as the first polymer88, such that the composition of the first bulk layer 90 may besubstantially the same as that of the microlayers 60. Alternatively, thesecond polymer 92 may be different from the first polymer 88, such thatthe composition of the first layer 90 may be different from that of themicrolayers 60. Similarly, the composition of second bulk layer 96 maybe the same or different from that of first layer 90, and also the sameor different from that of the microlayers 60.

As a further variation, a first intermediate bulk layer 98 may beinterposed between the first outer layer 90 and the microlayer section60 in shrink film 94. Similarly, a second intermediate bulk layer 100may be interposed between the second outer layer 96 and the microlayersection 60. The composition of layers 90 and 98 may be the same ordifferent. Similarly, the composition of layers 96 and 100 may be thesame or different. First intermediate bulk layer 98 may be formed frompolymer directed through distribution plate 32 b while secondintermediate bulk layer 100 may be formed from polymer directed throughdistribution plate 32 e (see FIGS. 2 and 5). If the composition oflayers 90 and 98 is the same, the same extruder 14 b may be used tosupply both of distribution plates 32 a and 32 b. If the composition ofsuch layers is different, two different extruders are used to supply thedistribution plates 32 a and 32 b. The foregoing also applies to thesupply of polymer to distribution plates 32 d and 32 e.

To make the shrink film illustrated in FIG. 6, no polymer was suppliedto distribution plate 32 c. If polymer was supplied to distributionplate 32 c, the resultant shrink film would have an additionalintermediate bulk layer between layer 98 and microlayer section 60.

Shrink film 94, as illustrated in FIG. 6, is representative of many ofthe inventive shrink films described in the Examples below, in that suchfilms have a total of twenty five (25) microlayers in the core of thefilm. The die used to make such films was essentially as illustrated inFIG. 2, except that twenty five (25) microlayer plates were included inthe microlayer assembly 34. For simplicity of illustration, only fifteen(15) microlayer plates are shown in the microlayer assembly 34 of die 12in FIG. 2. Generally, the microlayer section 60 may comprise any desirednumber of microlayers, e.g., between 2 and 50 microlayers, such asbetween 10 and 40 microlayers, etc.

Each of the microlayers 60 may have substantially the same composition.This would be the case, e.g., if all microlayer plates 48 were suppliedwith polymer by extruder 14 a. Alternatively, at least one of themicrolayers 60 may have a composition that is different from thecomposition of at least one other of the microlayers, i.e., two or moreof the microlayers may have compositions that are different from oneother. This can be accomplished, e.g., by employing extruder 80 tosupply a different polymer (i.e., different from the polymer supplied byextruder 14 a) to at least one of the microlayer plates 48. Thus, asshown in FIGS. 1 and 2, extruder 14 a may supply the “odd” microlayerplates (i.e., plates 48 a, c, e, etc.) with one type of polymericcomposition, e.g., “composition A,” while extruder 80 supplies the“even” microlayer plates (i.e., plates 48 b, d, f, etc.) with anothertype of polymeric composition, e.g., “composition B,” such that themicrolayer section 60 will comprise alternating microlayers of “A” and“B”, i.e., ABABAB . . . . A third extruder supplying a polymericcomposition “C” could also be employed, e.g., to provide a repeating“ABC” ordering of the microlayers, i.e., ABCABC . . . . Numerous othervariations are, of course, possible.

Each of the microlayers 60 in heat-shrinkable film 94 may havesubstantially the same thickness. Alternatively, at least one of themicrolayers may have a thickness that is different from the thickness ofat least one other of the microlayers. The thickness of the microlayers60 in shrink film 94 will be determined by a number of factors,including the construction of the microlayer plates, e.g., the spacing“M” of the fluid outlet 52 (FIG. 5), the mass flow rate of fluidizedpolymer that is directed through each plate, the degree of stretching towhich the tape 22/shrink film 94 is subjected during orientation, etc.

In accordance with the present invention, each of the microlayers 60 inshrink film 94 have a thickness that is significantly less than that ofthe bulk layers in the film, i.e., those produced by the relativelythick distribution plates 32. For example, the ratio of the thickness ofany of the microlayers 60 to the thickness of bulk layer 90 may rangefrom about 1:2 to about 1:40, e.g., from about 1:5 to about 1:30 (see,FIG. 6). The same thickness ratio range may apply to each of themicrolayers 60 relative any of the other bulk layers in shrink film 94,e.g., second outer layer 96 or intermediate layers 98 and/or 100. Thus,for example, each of the microlayers 60 may have a thickness rangingfrom about 0.001 to about 0.015 mils, while each of the bulk layers 90,96, 98 and/or 100 may have a thickness ranging from about 0.03 to about0.5 mils.

During the stretch-orientation process to which the tape 22 is subjectedto convert it into shrink film 94, the tape 22 may be oriented such thatthe film 94 has an orientation ratio of at least 3, as measured in atleast one direction along a length or width dimension of the film, e.g.,the transverse direction (TD) or machine direction (MD). Advantageously,the inclusion of microlayers in a heat-shrinkable film was found toprovide the film with the ability to be stretched at even higherorientation ratios, e.g., an orientation of at least 5, as measured inat least one direction along a length or width dimension of the film. Asshown in the Examples, films in accordance with the present inventionwere able to be oriented at a “5×5” ratio, i.e., the tape was stretchedto five times its original width and five times its original lengthduring the stretch-orientation process, such that the resultant film wasnot only rendered heat-shrinkable, but was twenty five (25) times itsoriginal size (surface area), when it was as an extruded tape emergingfrom die 12. Surprisingly, films in accordance with the presentinvention could even be stretched at an orientation ratio of 6×6, i.e.,the resultant shrink film was stretched to thirty six (36) times itsoriginal size as when it was an extruded tape (see, Examples 13-15, 22,and 63-71). Such high orientation ratios are advantageous because theyallow for a high degree of process efficiency in terms of through-putand polymer usage, which allows a greater amount of film to be producedfrom a given extrusion system. Conventional films (i.e., withoutmicrolayers) of comparable thickness could not be oriented at ratios anyhigher than 5×5 without destroying the film in the orientation process.Further, despite being stretched to a higher degree, the shrink films ofthe invention maintained physical properties that were on par withconventional films having a lower orientation ratio. Surprisingly,certain properties, such as instrumented impact strength (ASTMD3763-06), actually increased over those of the correspondingcomparative film having a lower orientation ratio (compare, e.g., theinstrumented impact strengths of Comparative Example 3 vs. InventiveExamples 63-71).

In many applications, shrink films are used in conjunction withautomated shrink-wrap packaging machines. As generally known by those ofordinary skill in the art of shrink film packaging, Elemendorf TearResistance (as opposed to other types of tear strength tests) representsthe most accurate predictive indicator of the tear performance of ashrink film in an automated shrink-wrap packaging machine. ElmendorfTear values are determined in accordance with ASTM D1922-06a, entitled“Standard Test Method for Propagation Tear Resistance of Plastic Filmand Thin Sheeting by Pendulum Method (Elmendorf Tear).” The D1922-06aElmendorf Tear test measures the average force to propagate tearingthrough a specified length of plastic film after the tear has beenstarted, using an Elmendorf-type tearing tester, which applies a tearingforce to the film from the force of a falling pendulum.

In automated shrink-wrap packaging machines, shrink films are subjectedto numerous folding and bending moves as the film is manipulated by themachine to envelop the object to be packaged, which initiate tears andplace tear propagation stresses on the film. Shrink films having arelatively low Elemendorf Tear resistance exhibit a relatively high rateof tearing in automated shrink packaging machines; conversely, thosehaving a relatively high Elemendorf Tear resistance have a relativelylow rate of machine tearing. Applicants have determined that shrinkfilms having an Elemendorf Tear value of at least 10 grams are capableof good performance with minimal tearing in almost all types and brandsof shrink packaging equipment. When shrink films have an Elemendorf Tearresistance of lower than 10 grams, such films are limited in their useto either manually-operated shrink-wrap machinery, or highly refined andexpensive machines that are designed to minimize the tear stressesplaced on the shrink film.

An unexpected benefit that was found to result from the inclusion ofmicrolayers in a shrink-film was an increase in Elemendorf Tearresistance. In a majority of the films produced in accordance with thepresent invention, this increase was found to be sufficientlysignificant that the thickness of such films could be reduced by 50%while still maintaining an Elmendorf Tear of greater than 10 grams, andalso maintaining the other properties necessary for such films toperform successfully in automated shrink-film packaging equipment. As aresult, the amount of polymer required to make such films caneffectively be cut in half, thus saving petroleum and natural gasresources, as well as reducing landfill space and cost.

The foregoing is demonstrated in further detail in the Examples below.The Elmendorf Tear values for films 1-23 are shown graphically in FIG.7. Films 1-3 are comparative films (no microlayers); films 4-23 are inaccordance with the present invention (microlayered core). Comparativefilm 3 had a thickness of 0.6 mil while inventive films 4-23 had halfthat thickness—0.3 mil. As shown in FIG. 7, the majority of the films inaccordance with the present invention, having a thickness of only 0.3mils, had an Elmendorf Tear resistance of 10 grams or more, similar tothe 0.6 mil film of comparative film 3. It is believed that thisunexpectedly strong Elmendorf tear-resistance, even in shrink-filmshaving a thickness of only 0.3 mil, is due to the presence ofmicrolayers in such films.

In accordance with an advantageous embodiment of the present invention,therefore, heat-shrinkable film 94 may have a thickness of less thanabout 0.7 mil and an Elmendorf Tear value (ASTM D1922-06a) of at least10 grams, as measured in at least one direction along a length or widthdimension of film. In terms of material (polymer) savings, film 94 mayhave an even lower thickness, e.g., less than about 0.65 mil, such asless than about 0.6 mil, less than about 0.55 mil, less than about 0.5mil, less than about 0.45 mil, less than about 0.4 mil, or less thanabout 0.35 mil, and still exhibit an Elmendorf Tear resistance of atleast about 10 grams.

If desired, all of the microlayers 60 may comprise a single polymer.Alternatively, at least one of the microlayers 60 may comprise a blendof two or more polymers. As indicated in the Examples below, the filmsin which at least one of the microlayers included a blend of twopolymers exhibited particularly good Elmendorf tear-resistance, despitea thickness of only 0.3 mil (see, Examples 4-13). Similarly, theExamples in which the microlayers alternated between two differentpolymeric compositions, i.e., with every other microlayer having adifferent composition, also exhibited particularly good Elmendorf Tearresistance.

Significantly, and regardless of the thickness of the shrink film,superior Elmendorf Tear results were found when at least one of themicrolayers comprises a blend of two more polymers and has a compositionthat is different from at least one other microlayer. Thus, for example,microlayer section 60 may comprise a repeating sequence of layersrepresented by the structure:A/B,wherein,

A represents a microlayer comprising one or more polymers,

B represents a microlayer comprising a blend of two or more polymers,and

A has a composition that is different from that of B.

The inventors have found that, when microlayer section 60 has theforegoing layer sequence, superior Elmendorf Tear results are obtained,regardless of the thickness of the film. Specifically, it was found thatshrink films having the foregoing “A/B” sequence generally exhibit a“normalized” (independent of film thickness) Elmendorf Tear value (ASTMD1922-06a) of at least about 30 grams/mil, as measured in at least onedirection along a length or width dimension of the film. Thisadvantageous trend is shown below in Examples 4-13 (0.3 mil), 17 (0.3mil), 45-49 (0.6 mil), 51 (0.5 mil), 53 (0.75 mil), 55-57 (1.0 mil), and60-62 (2.0 mil), wherein the inventive films compare favorably withtheir respective Comparative Examples of the same film thickness.

Thus, for example, the 0.3 mil films of Examples 4-13 and 17 generallyhave significantly higher normalized Elmendorf Tear than that of the 0.3mil Comparative Examples 1 and 2 (Tables 1-3). Similarly, the inventive0.6 mil films of Examples 45-49 exhibit significantly higher normalizedElmendorf Tear than the 0.6 mil Comparative film 3 (Tables 9-10).Likewise, the 0.5 mil film of inventive Example 51 was far greater thanthat of 0.52 mil Comparative Example 50, while the 0.75 mil inventivefilms of Example 53 exhibited markedly higher Elmendorf Tear than thecounterpart 0.75 mil Comparative Example 52 (Table 11). With respect tothe 1 mil and 2 mil films described in the Examples, the sameconsiderations apply, i.e., the Elmendorf Tear values of inventive films55-57 and 60-62 are higher than the corresponding Comparative films 54and 58-59, respectively (Tables 11-12). Interestingly, inventiveExamples 55 and 60 exhibited improved Elmendorf Tear despite havingrecycled polymer (“Repro-1”), which conventionally results in reducedElmendorf Tear.

Also noteworthy is that Examples 17-20 each contain recycled material(“Repro-1” or “Repro-2”) in the microlayer section, but only in Example17 does at least one of the microlayers have a composition that isdifferent from at least one other microlayer. As a result, the ElmendorfTear of Example 17 is higher than that of the other Examples 18-20.Surprisingly, while the addition of recycled polymer would normally beexpected to reduce the Elmendorf Tear of a film, the Elmendorf Tear ofExample 17 is higher than that of Comparative examples 1 and 2, whichcontain no recycled polymer. Similarly, the Elmendorf Tear of the filmsof Examples 45-47, which contain recycled polymer in the microlayersection, are surprisingly far superior to that of Comparative example 3,which contains no recycled polymer.

The repeating sequence of the “A/B” layers may, as shown in many of theExamples, have no intervening layers, i.e., wherein the microlayersection 60 contains only layers “A” and “B” as described above (withlayer “B” being a blend of two or more polymers). Alternatively, one ormore intervening layers may be present between the “A” and “B” layers,e.g., a microlayer “C”, comprising a polymer or polymer blend that isdifferent from those in the “A” and “B” microlayers, such that therepeating sequence of layers has the structure “A/B/C/A/B/C . . . ”,“A/C/B/A/C/B . . . ”, etc. Other sequences are, of course, alsopossible. For instance, the film of inventive Examples 45-46 have thepattern “A/A/B/A/A/B . . . ”, while inventive Example 47 has the pattern“A/B/B/A/B/B . . . .” The “A/B” (or A/B/C, A/A/B, A/B/B, etc.) sequencemay be repeated as many times as necessary to obtain a desired number ofmicrolayers in microlayer section 60.

In Example 45, microlayer “B” is “Repro-1,” which is a blend of recycledpolymers. Microlayer B (or A) may comprise between 1 and 50 weightpercent recycled polymer, based on the total weight of the film (the useof recycled polymers is described more fully below). More generally, asillustrated in the Examples, microlayers A and/or B may comprise one ormore of ethylene/alpha-olefin copolymer, ethylene/vinyl acetatecopolymer, polypropylene homopolymers or copolymer, ethylene/methacrylicacid copolymer, maleic anhydride-grafted polyethylene, polyamide, and/orlow density polyethylene. The foregoing polymers may be obtained from“virgin” resin and/or from recycled polymer, and may be employed in eachlayer individually or as blends of two or more of the resins.

Still more generally, in the production of heat-shrinkable films inaccordance with the present invention, the fluid layers coextruded bydie 12, including both the bulk layers and microlayers, may comprise oneor more molten thermoplastic polymers. Examples of such polymers includepolyolefins, polyesters (e.g., PET and PETG), polystyrenes, (e.g.,modified styrenic polymers such as SEBS, SBS, etc.), polyamidehomopolymers and copolymers (e.g. PA6, PA12, PA6/12, etc.),polycarbonates, etc. Within the family of polyolefins, variouspolyethylene homopolymers and copolymers may be used, as well aspolypropylene homopolymers and copolymers (e.g., propylene/ethylenecopolymer). Polyethylene homopolymers may include low densitypolyethylene (LDPE) and high density polyethylene (HDPE). Suitablepolyethylene copolymers may include a wide variety of polymers, such as,e.g., ionomers, ethylene/vinyl acetate (EVA), ethylene/vinyl alcohol(EVOH), and ethylene/alpha-olefins, including heterogeneous(Zeigler-Natta catalyzed) and homogeneous (metallocene, single-citecatalyzed) ethylene/alpha-olefin copolymers. Ethylene/alpha-olefincopolymers are copolymers of ethylene with one or more comonomersselected from C₃ to C₂₀ alpha-olefins, such as 1-butene, 1-pentene,1-hexene, 1-octene, methyl pentene and the like, including linear lowdensity polyethylene (LLDPE), linear medium density polyethylene (MDPE),very low density polyethylene (VLDPE), and ultra-low densitypolyethylene (ULDPE).

As alluded to above, a further advantage of the present inventionpertains to the use of recycled polymer in heat-shrinkable films. Incommercial film-manufacturing operations, the production andaccumulation of scrap film is, and has always been, a logistical andeconomic problem. Scrap film results from a variety of sources—initialproduction of multilayer films prior to steady-state operation;out-of-spec (improperly formed) film; portions of film that aremechanically trimmed and separated from the main film web in order toachieve a predetermined web width; etc. As may be appreciated, scrapgenerally cannot be used for its originally-intended commercialapplication. However, it nevertheless represents an economic andresource investment in polymers derived from the Earth's petroleum andnatural gas reserves.

Fortunately, scrap film can be reprocessed, e.g., by grinding,remelting, and pelletizing the scrap, and can then be blended with‘virgin’ polymer in the production of many types of films.Unfortunately, the incorporation of such reprocessed scrap polymer inconventional shrink films, particularly thin shrink films having athickness of less than about 1 mil, has proven quite difficult toachieve in meaningful amounts. For example, it was found thatconventional shrink films, having a thickness of 0.6 mil, can includeonly up to about 16 wt. % recycled polymer. The inclusion of additionalrecycled polymer was found to result in film breakage duringstretch-orientation, e.g., bubble rupture, when stretching using theblown bubble process. For shrink films having a lower thickness, evenless recycled polymer can be included. For example, in conventionalshrink films having a thickness of 0.3 mil, no recycled polymer could beadded to the film; attempts to add any recycled polymer resulted in filmbreakage during stretch-orientation.

Surprisingly, the inventors discovered that microlayering allows a fargreater percentage of recycled polymer to be included in shrink filmsthan when such films are made in a conventional fashion, i.e., withoutmicrolayering. This unexpected benefit occurs when at least one of themicrolayers comprises recycled polymer. For example, the microlayersection 60 may comprise between 1 and 50 weight percent recycledpolymer, based on the total weight of the film. Perhaps even moresurprising, the foregoing weight percentages of recycled polymer may beachieved in shrink films having a thickness of only about 0.3 mil, andyet the films did not break during stretch-orientation. As shown belowin Example 5, for instance, twelve of the twenty five microlayers in thecore contained a blend of 50 wt. % LLDPE and 50 wt. %recycled/reprocessed scrap polymer (“Repro-1”), for a total of about12.5 wt. % recycled polymer in the film. Not only could the film ofExample 5 be successfully stretch-oriented to make a shrink film havinga thickness of 0.3 mil, but it exhibited Elemendorf Tear values inexcess of 10 grams in both the machine direction and in the transversedirection.

Examples 17-20 were similarly able to be stretch-oriented into a 0.3 milshrink film, but with much higher amounts of recycled polymer. Example17 had 36 wt. % recycled polymer, while Example 18 had 40 wt. %, andboth had Elmendorf Tear values in excess of 10 grams. Examples 19-20each had 25 wt. % recycled polymer.

The beneficial increase in the amount of scrap/recycled polymer that canbe incorporated into shrink films, as a result of including suchrecycled polymer in microlayers in accordance with the presentinvention, allows a further saving of petroleum and natural gasresources, as well as a reduction in landfill space and cost.

Another surprising result of the employment of microlayers in a shrinkfilm is a significant increase in the tensile elongation at yield (ASTMD-882) along the longitudinal/machine direction of the film. Asdemonstrated in the Examples below, the tensile elongation of films inaccordance with the present invention were found to be significantlyhigher than those of their corresponding comparative films. Suchincrease is advantage in that shrink films of the invention are lesslikely to break under a given load than a similar conventional shrinkfilm.

A further unexpected benefit discovered by the inventors was that theemployment of microlayers in a shrink film allows the use of lessexpensive polymers to achieve the same performance characteristics ascomparable films having more expensive polymers. In the case ofethylene/alpha-olefin copolymers, for example, ethylene/octenecopolymers are generally more expensive but higher-performing thanethylene/hexene copolymers. Examples 8, 9, 15, 19, and 23 below eachemploy ethylene/hexene copolymer(s) in the microlayered core of suchfilms. As indicated by the test results in Examples 33 and 34, theperformance characteristics of such films were on par with the films ofthe other Examples, which employed more expensive ethylene/octenecopolymers in the core. Also, while Comparative film 59 exhibited fairlygood Elmendorf Tear, it relies on the inclusion of a relativelyexpensive/exotic material, SBS (styrene-butadiene-styrene copolymer), inthe core of the film, as opposed to the relativelylower-performing/less-expensive polyethylenes used in the inventivefilms of Examples 60-62. However, the microlayering of suchpolyethylenes in the shrink films of the present invention unexpectedlyimproved the Elmendorf Tear of such films, thereby eliminating the needto use expensive and exotic resins to achieve high performance.

Multilayer, heat-shrinkable films in accordance with the presentinvention preferably have a total free shrink (ASTM D2732-03) of atleast about 10% at 200° F., such as about 15% or greater, about 20% orgreater, etc. Total free shrink is the sum of the free shrink in boththe TD and LD, as tested per ASTM D2732-03.

FIG. 8 illustrates an alternative embodiment of the invention, in whichthe microlayer section 60 is positioned at an exterior surface of thefilm, such that one of the microlayers forms an outer layer 102 for theresultant heat-shrinkable, multilayer film 104. Thus, in contrast toshrink film 94, in which the microlayer section 60 is in the interior ofthe film, in shrink film 104, the microlayer section 60 is positioned atthe outside of the film such that microlayer 102 forms an outer layerfor the film. Film 104 may be formed from die 12 as described above inrelation to film 94, except that no fluidized polymer would be directedthrough distribution plates 32 d or 32 e such that bulk layers 96 and100 are omitted from the film structure. In the resultant tube 22 thatemerges from die 12, bulk layer 90 would thus be the inner-most layer ofthe tube while microlayer 102 would form the outer-most layer. Such tube22 is then stretch-oriented as described above, e.g., via the blownbubble or tenterframe process, to make shrink film 104.

As an alternative, shrink film 104 may be converted into a shrink filmhaving a pair of microlayers 102 on both of the opposing outer layers ofthe film. To make such a film, die 12 may be configured as describedimmediately above, with the resultant tube 22 being stretch-oriented viathe blown bubble process to make shrink film 104 in the form of aheat-shrinkable/expanded tube. Such expanded tube may then be collapsedand welded together such that the inner bulk layer 90 adheres to itself.The resultant shrink film has microlayer section 60 on both outersurfaces of the film, with a pair of bulk layers 90 in the center of thefilm, and a pair of intermediate bulk layers 98 spaced from one anotherby the pair of bulk layers 90. In this configuration, a pair ofmicrolayers 102 forms both of the opposing outer layers for the film.Such film thus has microlayered “skins” with one or more bulk layers inthe core. If desired, a material may be included at the inner-most layerof the tube to facilitate the welding of the tube to itself, e.g., alayer of EVA or an adhesive, e.g., anhydride-grafted polymer, which maybe directed through plate 32 a of die 12, with bulk layers 90 and 98being formed from plates 32 b and 32 c, respectively. The filmsdescribed below in Examples 72 and 74-76 were prepared in this manner.

If desired, a second microlayer assembly 34 may be added to die 12,which forms a second microlayer section in the resultant shrink film.Accordingly, another way to form a shrink film having a microlayersection at both outer surfaces of the film is to configure die 12 suchthe distribution plates 32 are sandwiched between both microlayerassemblies 34. Such configuration will produce a shrink film havingmicrolayered skins with one or more bulk layers in the core, without theneed to collapse and weld the inflated tube as described above.

An alternative configuration of die 12 will also result in shrink film104 as shown in FIG. 8. In such configuration, the supply of fluidizedpolymer to die 12 may be arranged such that microlayered fluid mass 60is deposited onto primary forming stem 30 prior to the deposition ofbulk layer 90 onto the primary forming stem 30. In this manner, themicrolayered fluid mass 60 is interposed between the bulk layer 90 andprimary forming stem 30. In this case, with reference to FIG. 2, nofluidized polymer would be supplied to distribution plates 32 a-c.Instead, the bulk layer 90 would be formed by supplying fluidizedpolymer to distribution plate 32 e, and the intermediate bulk layer 98would be formed by supplying fluidized polymer to distribution plate 32d. In the resultant tube 22 that emerges from die 12, bulk layer 90would thus be the outer-most layer of the tube while microlayer 102would form the inner-most layer. Such tube 22 is then stretch-orientedas described above, e.g., via the blown bubble or tenterframe process,to make shrink film 104.

The invention will now be further described in the following examples.

EXAMPLES

The materials used in the examples are identified below:

-   1. MDPE-1: Dowlex 2037; a homogeneous ethylene/octene copolymer    medium density polyethylene, having a melt flow index of 2.5 g/10    min (ASTM D-1238), a specific gravity of 0.9350 g/cc (ASTM D-792), a    melting point of 124.7° C. (Dow's Internal Method) and a Vicat    softening point of 118.9° C. (ASTM D1525); purchased from Dow    Chemicals.-   2. MDPE-2: M3105; a homogeneous ethylene/octene copolymer medium    density polyethylene, having a melt flow index of 2.2 g/10 min (ASTM    D-1238), a density of 0.9360 g/cc (ASTM D-1505); purchased from    Flint Hill Resources.-   3. MDPE-3: Dowlex 2036G; a homogeneous ethylene/octene copolymer    medium density polyethylene, having a melt flow index of 2.5 g/10    min (ASTM D-1238), a specific gravity of 0.9370 g/cc (ASTM D-792), a    melting point of 125° C. (Dow's Internal Method) and a Vicat    softening point of 118.9° C. (ASTM D1525); purchased from Dow    Chemicals.-   4. EVA-1: EVA 1335; an ethylene/vinyl acetate copolymer with 3.3%    vinyl acetate content, giving a melt flow index of 2.0 g/10 min    (ASTM D-1238), a density of 0.9240 g/cc (ASTM D-1505) and a melting    point of 104.7° C.; purchased from Flint Hill Resources.-   5. EVA-2: EF437AA; an ethylene/vinyl acetate copolymer with 2.5%    vinyl acetate content, giving a melt flow index of 2.0 g/10 min    (ASTM D-1238), a density of 0.9250 g/cc (ASTM D-1505); purchased    from Westlake Chemicals.-   6. EVA-3: Escorene LD318.92; an ethylene/vinyl acetate copolymer    with 8.7% vinyl acetate content, giving a melt flow index of 2.0    g/10 min (ASTM D-1238), a density of 0.9300 g/cc (ASTM D-1505) and a    Vicat softening point of 81.1° C. (ASTM D-1525); purchased from    Exxon Mobil.-   7. EVA-4: Escorene LD761.36; an ethylene/vinyl acetate copolymer    with more than 20.0% vinyl acetate content, giving a melt flow index    of 5.75 g/10 min (ASTM D-1238), a density of 0.9500 g/cc (ASTM    D-1505) and a melting point of 72.0° C. (ASTM D-1525); purchased    from Exxon Mobil.-   8. MB1: an internally compounded Medium Density Polyethylene    masterbatch containing 2.00% n,n′-ethylene bis-stearamide, 1.67%    erucamide and 3.33% anhydrous aluminum silicate with a density of    0.955 g/cc (ASTM D-1505).-   9. MB2: an internally compounded ethylene/vinyl acetate copolymer    masterbatch with 3.29% n,n′-ethylene bis-stearamide, 1.35%    erucamide, 1.1% zinc stearate, 1.4% amorphous silica with erucamide,    0.66% amorphous silica with oleamide and 0.70%    alkali-alumino-silicate ceramic beads with a density of 0.938 g/cc    (ASTM D-1505).-   10. MB3: an internally compounded ethylene/vinyl acetate copolymer    masterbatch with 1.8% n,n′-ethylene bis-stearamide, 3.8% erucamide,    1.9% oleamide and 1.0% zinc stearate with a density of 0.922 g/cc    (ASTM D-1505).-   11. MB4: an internally compounded Medium Density Polyethylene    masterbatch containing 3.00% n,n′-ethylene bis-stearamide, 4.00%    erucamide and 3.00% anhydrous aluminum silicate with a density of    0.955 g/cc (ASTM D-1505).-   12. MB5: an internally compounded ethylene/vinyl acetate copolymer    masterbatch with 3.30% n,n′-ethylene bis-stearamide, 1.70%    diatomaceous earth.-   13. MB6: an internally compounded ethylene/vinyl acetate copolymer    masterbatch with 3.30% n,n′-ethylene bis-stearamide, 1.70%    diatomaceous earth, 0.80% behenamide and 3.4% erucamide with a    density of 0.933 g/cc.-   14. VLDPE-1: Exceed 1012CA; an ethylene/hexene copolymer very low    density polyethylene, produced by single site metallocene catalysis,    with a melt index of 1.0 g/10 min (ASTM D-1238) and a density of    0.912 g/cc (ASTM D-1505); purchased from Exxon Mobil.-   15. VLDPE-2: Affinity PF 1140G; a branched ethylene/octene copolymer    very low density polyethylene, produced by INSITE technology, with a    melt index of 1.60 g/10 min (ASTM D-1238) and a specific gravity of    0.8990 g/cc (ASTM D-792) having 14% octane content, a Vicat    softening point of 77° C. (ASTM D-1525) and a melting point of    96.1° C. (Dow's Internal Method): purchased from Dow Chemicals.-   16. VLDPE-3: Affinity PL 1881G; a branched ethylene/octene copolymer    very low density polyethylene, produced by INSITE technology, with a    melt index of 1.00 g/10 min (ASTM D-1238) and a specific gravity of    0.906 g/cc (ASTM D-79.2), a Vicat softening point of 86.1° C. (ASTM    D-1525) and a melting point of 100° C. (Dow's Internal Method);    purchased from Dow Chemicals.-   17. VLDPE-4: Exact 3132; a linear ethylene/hexene copolymer very low    density polyethylene, produced by single site catalyst, with a melt    index of 1.20 g/10 min (ASTM D-1238) and a density of 0.900 g/cc    (ASTM D-1505) a Vicat softening point of 87.6° C. and a melting    point of 96.0° C.; purchased from ExxonMobil.-   18. VLDPE-5: Attane 4203; a linear ethylene/octene copolymer very    low density polyethylene, produced by Ziegler-Natta catalyst, with a    melt index of 0.80 g/10 min (ASTM D-1238), a specific gravity of    0.9070 g/cc (ASTM D-792 a Vicat softening point of 83.8° C. (ASTM    D-1525) and a melting point of 122.8° C. (Dow's Internal Method);    purchased from Dow Chemicals.-   19. SBS-1: Styroflex 2G 66: a styrene-butadiene block copolymer with    at least 65% styrene content and at least 70% butadiene content    having a melt flow of 12.5 g/cc (ASTM D-1238), a specific gravity of    1.000 g/cc (ASTM D-792) and a Vicat softening point of 47.8° C.    (ASTM D-1525); purchased from BASF.-   20. SBS-2: Styrolux HS 70; a styrene/butadiene copolymer having a    melt flow of 13.0 g/cc (ASTM D-1238), a specific gravity of 1.020    g/cc (ASTM D-792) and a Vicat softening point of 72.2° C. (ASTM    D-1525); purchased from BASF.-   21. LLDPE-1: Dowlex 2045; a homogeneous ethylene/octene copolymer,    having a melt flow index of 1.0 g/10 min (ASTM D-1238), a specific    gravity of 0.9200 g/cc (ASTM D-792), a Vicat softening point of    107.8° C. (ASTM D-1525) and a melting temperature of 122.2° C.    (Dow's Internal Method); purchased from Dow Chemicals.-   22. LLDPE-2: LL 3001.63; a linear ethylene/hexene copolymer made    using Ziegler-Natta catalyst in gas phase having a melt flow index    of 1.0 g/10 min (ASTM D-1238), a density of 0.917 g/cc (ASTM D-1505)    and a melting temperature of 125° C.; purchased from ExxonMobil.-   23. LLDPE-3: SC74858-F; a linear ethylene/hexene copolymer made    using Ziegler-Natta catalyst in gas phase having a melt flow index    of 0.5 g/10 min (ASTM D-1238), a density of 0.917 g/cc (ASTM D-1505)    and melting temperature of 121° C.; purchased from Westlake    Chemical.-   24. LLDPE-4: LL 10001.32; a linear ethylene/butene copolymer made    using Ziegler-Natta catalyst in gas phase having a melt flow index    of 1.0 g/10 min (ASTM D-1238), a density of 0.918 g/cc (ASTM D-1505)    and a melting temperature of 121° C.; purchased from ExxonMobil.-   25. Repro-1: an in-house reclaim of reprocessed, scrap multipurpose    shrink film, which contained approximately 93.0% ethylene/octene    copolymer, 6.0% ethylene/vinyl acetate copolymer and less than 1.0%    other additives.-   26. Repro-2: an in-house reclaim of reprocessed, scrap laminate    films containing approximately 22% polypropylene, 8% linear low    density polyethylene, 20% zinc neutralized ethylene methacrylic acid    polymer, 15% maleic anhydride grafter polyethylene, 24% total    polyamide 6 and 6/66 and 10% ethylene-vinyl acetate copolymer.-   27. Repro-3: an in-house reclaim of reprocessed, scrap laminate    films containing approximately 50.6% linear low density    polyethylene, 13.5% low density polyethylene, 30.0% polyamide 6 and    5.9% hydrolyzed-ethylene-vinyl acetate copolymer.

Example 1 Comparative

A comparative multilayer film was made and had the following three-layerstructure with a total film thickness of 0.30 mils:

-   Layer 1: 44% MDPE-1+40% EVA-1+16% MB1 (20% of total thickness of    layers 1-3)-   Layer 2: 60% LLDPE-1+40% MDPE-1 (60% of total thickness layers 1-3)-   Layer 3: 44% MDPE-1+40% EVA-1+16% MB1 (20% of total thickness layers    1-3)

The film was fully coextruded and then stretch-oriented by the blownbubble coextrusion process as described above and, e.g., in U.S. Pat.Nos. 3,022,543 and 4,551,380. The film was first coextruded as tapeusing an annular 5-layer or 3-layer die, followed by a water quench uponexiting the die. The tape was then subjected to electron beamirradiation to promote cross-linking, at a dosage of between 15 and 35kGy (approximated values), and then preheated in an oven fororientation. The tape was then oriented as a bubble at an orientationratio of approximately 5×5 in both the Longitudinal Direction (LD) andTransverse Direction (TD). An air ring was used to quench the orientedfilm. The bubble was then collapsed and wound into a film roll.

Example 2 Comparative

A comparative multilayer film was made by the process described abovefor Comparative Example 1, and had the following five-layer structurewith a total film thickness of 0.30 mils:

-   Layer 1: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-5)-   Layer 2: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-5)-   Layer 3: LLDPE-1 (50.0% of total thickness of layers 1-5)-   Layer 4: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-5)-   Layer 5: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-5)

Example 3 Comparative

A comparative multilayer film was made by the process described abovefor Comparative Example 1, and had the following five-layer structurewith total film thickness of 0.60 mils:

-   Layer 1: 47.8% LLDPE-1+27.6% MDPE-1+14.5% EVA-1+14% MB2 (12.5% of    total thickness of layers 1-5)-   Layer 2: 47.8% LLDPE-1+27.6% MDPE-1+14.5% EVA-1+14% MB3 (12.5% of    total thickness of layers 1-5)-   Layer 3: LLDPE-1 (50.0% of total thickness of layers 1-5)-   Layer 4: 47.8% LLDPE-1+27.6% MDPE-1+14.5% EVA-1+14% MB3 (12.5% of    total thickness of layers 1-5)-   Layer 5: 47.8% LLDPE-1+27.6% MDPE-1+14.5% EVA-1+14% MB2 (12.5% of    total thickness of layers 1-5)

Example 4

A multilayer film in accordance with the present invention was made andhad the following twenty nine-layer structure, with a total filmthickness of 0.30 mils:

-   Layers 1, 2: 44% MDPE-1+40% EVA-1+16% MB1 (20% of total thickness of    layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   30% MDPE-1+70% LLDPE-1 (3.33% of total thickness of layers 1-29)-   Layer 28, 29: 44% MDPE-1+40% EVA-1+16% MB1 (20% of total thickness    of layers 1-29)

The film was fully coextruded and stretch-oriented via a blown bubbleprocess as in Example 1. However, the film was first coextruded as atape using an annular 29-layer multilayer die, followed by a waterquench upon exiting the die. The die was as described above andillustrated in FIG. 2, except that the microlayer assembly included atotal of 25 microlayer distribution plates. Fluidized (molten) polymerwas supplied to each of the microlayer distribution plates. Fluidizedpolymer was supplied only to distribution plates 32 a, b, d, and e; nopolymer was supplied to plate 32 c. The resultant 29-layer structurecomprised a core with 25 microlayers (layers 3-27), plus 4 thickerlayers (layers 1-2 and 28-29). Thick layers 1-2 were positioned on oneside of the core and thick layers 28-29 were positioned on the otherside of the core, with layer 1 forming one of the outer layers and layer29 forming the other outer layer.

After extrusion, the tape was transported through a cross linking unit,in which it was irradiated with electron beams at between 15 and 35 kGy(approximated values), and then heated to its orientation temperature inan oven. The tape was then oriented into a bubble at an orientationratio of approximately 5×5 in the Longitudinal Direction (LD) and theTransverse Direction (TD) upon exiting the oven, and cooled by air blownfrom an annular ring. The bubble was then collapsed and wound into afilm roll.

Example 5

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layer 1: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)-   Layer 2: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   50% LLDPE-1+50% Repro-1 (2.09% of total thickness of layers        1-29)-   Layer 28: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layer 29: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)

Example 6

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-3 (1.92% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   60% LLDPE-1+40% MDPE-1 (2.08% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)

Example 7

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42%-44% MDPE-2 (or 42%-44% MDPE-3)+38%-40%    EVA-2+16%-20% MB4 (20.0% of total thickness of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.5% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   40% MDPE-2 (or 40% of MDPE-3)+60% LLDPE-1 (3.3% of total        thickness of layers 1-29)-   Layer 28, 29: 42%-44% MDPE-2 (or 42%-44% MDPE-3)+38%-40%    EVA-2+16%-20% MB4 (20.0% of total thickness of layers 1-29)

Example 8

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   50% VLDPE-1+50% LLDPE-2 (2.31% of total thickness of layers        1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-2 (2.50% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+22% MB4 (20.0% of total thickness    of layers 1-29)

Example 9

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   50% VLDPE-4+50% LLDPE-3 (2.31% of total thickness of layers        1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-3 (2.5% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)

Example 10

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   50% VLDPE-5+50% LLDPE-1 (1.92% of total thickness of layers        1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-1 (2.92% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)

Example 11

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-5 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   60% LLDPE-1+40% MDPE-2 (3.33% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)

Example 12

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   60% LLDPE-1+40% VLDPE-2 (1.92% of total thickness of layers        1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   50% MDPE-2+50% LLDPE-1 (2.08% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)

Example 13

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 44% MDPE-1+40% EVA-1+16% MB1 (20% of total thickness of    layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (2.31% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   50% MDPE-1+50% LLDPE-1 (2.50% of total thickness of layers 1-29)-   Layer 28, 29: 44% MDPE-1+40% EVA-1+16% MB1 (20% of total thickness    of layers 1-29)

Example 14

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layer 1: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)-   Layer 2: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layers 3 to 27:    -   LLDPE-1 (2.0% of total thickness of layers 1-29)-   Layer 28: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layer 29: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)

Example 15

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layer 1: 40% MDPE-1+40% EVA-1+20% MB4 (20% of total thickness of    layers 1-29)-   Layer 2: 40% MDPE-1 (or 40% MDPE-2)+60% LLDPE-1 (10% of total    thickness of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-1 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-1 (1.67% of total thickness of layers 1-29)-   Layer 28: 40% MDPE-1 (or 40% MDPE-2)+60% LLDPE-1 (10% of total    thickness of layers 1-29)-   Layer 29: 40% MDPE-1+40% EVA-1+20% MB4 (20% of total thickness of    layers 1-29)

Example 16

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layer 1: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)-   Layer 2: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layers 3 to 27:    -   LLDPE-1 (2.0% of total thickness of layers 1-29)-   Layer 28: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layer 29: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)

Example 17

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that 36 wt.% recycled material (“Repro-1”) was added to the microlayer section; theresultant film had the following twenty nine-layer structure with totalfilm thickness of 0.30 mils:

-   Layer 1: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)-   Layer 2: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   10% LLDPE-1+90% Repro-1 (3.33% of total thickness of layers        1-29)-   Layer 28: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)-   Layer 29: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)

Example 18

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that 40 wt.% recycled material (“Repro-1”) was added to the microlayer section; theresultant film had the following twenty nine-layer structure with totalfilm thickness of 0.30 mils:

-   Layer 1: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)-   Layer 2: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   60% LLDPE-1+40% Repro-1 (1.54% of total thickness of layers        1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   20% LLDPE-1+80% Repro-1 (3.33% of total thickness of layers        1-29)-   Layer 28: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)-   Layer 29: 42% MDPE-1+38% EVA-2+20% MB4 (10% of total thickness of    layers 1-29)

Example 19

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that 25 wt.% recycled material (“Repro-1”) was added to the microlayer section; theresultant film had the following twenty nine-layer structure with totalfilm thickness of 0.30 mils:

-   Layer 1: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)-   Layer 2: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layers 3 to 27:    -   50% LLDPE-1+50% Repro-1 (2.0% of total thickness of layers 1-29)-   Layer 28: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layer 29: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29

Example 20

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that 25 wt.% recycled material (“Repro-2”) was added to the microlayer section; theresultant film had the following twenty nine-layer structure with totalfilm thickness of 0.30 mils:

-   Layer 1: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)-   Layer 2: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layers 3 to 27:    -   50% LLDPE-1+50% Repro-2 (2.0% of total thickness of layers 1-29)-   Layer 28: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB3 (12.5% of    total thickness of layers 1-29)-   Layer 29: 44.5% LLDPE-1+22.1% MDPE-1+13.4% EVA-1+20% MB2 (12.5% of    total thickness of layers 1-29)

Example 21

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layer 1: 40% MDPE-1+40% EVA-1+20% MB4 (20% of total thickness of    layers 1-29)-   Layer 2: 40% MDPE-1 (or 40% MDPE-2)+60% LLDPE-1 (10% of total    thickness of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   VLDPE-1 (1.67% of total thickness of layers 1-29)-   Layer 28: 40% MDPE-1 (or 40% MDPE-2)+60% LLDPE-1 (10% of total    thickness of layers 1-29)-   Layer 29: 40% MDPE-1+40% EVA-1+20% MB4 (20% of total thickness of    layers 1-29)

Example 22

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (25.91% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-2 (2.21% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   SBS-2 (1.62% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (25.91% of total    thickness of layers 1-29)

Example 23

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-3 (1.92% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-1 (2.08% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)

Example 24

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   EVA-3 (1.92% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   MDPE-2 (2.08% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)

Example 25

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.30mils:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-1 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-2 (3.33% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29

In the following Examples 26-35, the described films were made inaccordance with Example 4, except that “melt ripples” (areas ofnon-uniform thickness) in the tape prevented the tape from beingoriented as a bubble. It is believed that such melt ripples resultedfrom excessive differences in the viscosities of adjacently-positionedpolymers in the microlayer section. Melt rippling can thus be avoided byroutine experimentation, e.g., by selecting polymers for adjacentpositioning in the microlayer section that have melt flow indices thatare as close as possible while still providing the properties desired ofsuch polymers.

Example 26

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (25% of total thickness of    layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-2 (2.68% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   SBS-2 (1.26% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (25% of total thickness    of layers 1-29)

Example 27

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-2 (1.9% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   MDPE-1 (2.1% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (25.0% of total thickness    of layers 1-29)

Example 28

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-4 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-2 or LLDPE-3 (3.33% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)

Example 29

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1, 2: 42% MDPE-1+38% EVA-1+20% MB4 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   40% VLDPE-2+60% LLDPE-1 (3.08% of total thickness of layers        1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   MDPE-2 (1.67% of total thickness of layers 1-29)-   Layer 28, 29: 42% MDPE-1+38% EVA-1+22% MB4 (20.0% of total thickness    of layers 1-29)

Example 30

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1, 2: 44% MDPE-1+40% EVA-1+16% MB1 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (2.77% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   MDPE-1 (2.00% of total thickness of layers 1-29)-   Layer 28, 29: 44% MDPE-1+40% EVA-1+16% MB1 (20.0% of total thickness    of layers 1-29)

Example 31

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1, 2: 44% MDPE-1+40% EVA-1+16% MB1 (20.0% of total thickness    of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (2.31% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   80% MDPE-1+20% LLDPE-1 (2.50% of total thickness of layers 1-29)-   Layer 28, 29: 44% MDPE-1+40% EVA-1+16% MB1 (20.0% of total thickness    of layers 1-29)

Example 32

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layer 1: 40% MDPE-1+40% EVA-1+20% MB4 (20% of total thickness of    layers 1-29)-   Layer 2: MDPE-1 (10% of total thickness of layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   VLDPE-1 (1.54% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   LLDPE-1 (1.67% of total thickness of layers 1-29)-   Layer 28: MDPE-1 (10% of total thickness of layers 1-29)-   Layer 29: 40% MDPE-1+40% EVA-1+20% MB4 (20% of total thickness of    layers 1-29)

Example 33

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layer 1: 40% MDPE-1+40% EVA-1+20% MB4 (16.5% of total thickness of    layers 1-29)-   Layer 2: 40% MDPE-1+40% VLDPE-1+20% MB4 (13% of total thickness of    layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   SBS-1 (1.53% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   50% MDPE-1+50% VLDPE-1 (1.75% of total thickness of layers 1-29)-   Layer 28: 40% MDPE-1+40% VLDPE-1+20% MB4 (13% of total thickness of    layers 1-29)-   Layer 29: 40% MDPE-1+40% EVA-1+20% MB4 (16.5% of total thickness of    layers 1-29)

Example 34

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layer 1: 40% MDPE-1+40% EVA-1+20% MB4 (16.5% of total thickness of    layers 1-29)-   Layer 2: 40% MDPE-1+40% VLDPE-1+20% MB4 (13% of total thickness of    layers 1-29)-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   70% SBS-1+30% SBS-2 (1.53% of total thickness of layers 1-29)-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26:    -   50% MDPE-1+50% VLDPE-1 (1.75% of total thickness of layers 1-29)-   Layer 28: 40% MDPE-1+40% VLDPE-1+20% MB4 (13% of total thickness of    layers 1-29)-   Layer 29: 40% MDPE-1+40% EVA-1+20% MB4 (16.5% of total thickness of    layers 1-29)

Example 35

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure with a targeted film thickness of 0.30 mil:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-1 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layers 3-27:    -   50% LLDPE-1+50% Repro-3 (2.0% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-1 (12.5% of    total thickness of layers 1-29);

Example 36

The films of Examples 1-25 were subjected to the following tests:

-   1) Tensile Strength and Elongation at yield: tested in both the    machine direction (MD) and transverse direction (TD) in accordance    with ASTM D-882; tensile strength is expressed in psi (pounds/in²)    and elongation is expressed in %.-   2) Young's Modulus: tested in both the machine direction (MD) and    transverse direction (TD) in accordance with ASTM D-882; expressed    in psi (pounds/in²).-   3) Propagation Tear Resistance by Pendulum Method (Elmendorf Tear):    tested in both the machine direction (MD) and transverse direction    (TD) in accordance with ASTM D-1922-06a to measure the average force    to propagate tearing through a length of film after the tear has    been started, using an Elmendorf-type tearing tester; Elmendorf Tear    is expressed in grams/mil (normalized, based on thickness of tested    film) and in grams (actual value, i.e., regardless of the thickness    of tested film).-   4) Instrumented Impact Strength: tested in accordance with ASTM    D3763-06 to measure high speed puncture properties of plastics using    load and displacement sensors; designed to provide load versus    deformation response of plastics under essentially multiaxial    deformation conditions at impact velocities; reported as peak load    and expressed in pounds force (lb_(f)—actual) and in lb_(f)/mil    (normalized).-   5) Initiation Tear Resistance (Graves Tear): tested in both the    machine direction (MD) and transverse direction (TD) in accordance    with ASTM D-1004 to measure the force to initiate tearing; Graves    Tear is expressed in grams/mil.-   6) Tear-Propagation Resistance (Trouser Tear): tested in both the    machine direction (MD) and transverse direction (TD) in accordance    with ASTM D-1938; expressed in grams/mil.-   7) Free Shrink: tested in both the machine direction (MD) and    transverse direction (TD) in accordance with ASTM D-2732-03; free    shrink is expressed in %.-   8) Haze: tested in accordance with ASTM D-1003; expressed in %.-   9) Clarity: tested in accordance with ASTM D-1746; expressed in %.-   10) Gloss: tested in accordance with ASTM D2457; expressed in %

The results are summarized in Tables 1-4.

TABLE 1 Examples Test 1^(3,4) 2³ 3^(3,5) 4 5 6 Resin 1 in microlayerLLDPE-1 + LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 VLDPE-3 Resin 2 in microlayerMDPE-1 MDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 Repro-1 MDPE-2 FilmThickness (mils) 0.3 0.3 0.6 0.3 0.3 0.3 Tensile Strength at 20.5/20.620.6/19.6 17.9/19.3 21.2/22.3 21.9/16.0 14.9/17.4 yield¹ (psi × 1000)Tensile Elongation at  85/110  94/100  94/100 96/85 95/86 120/84  yield¹(%) Elmendorf Tear¹ 26.8/28.1 25.9/22.3 25.6/26.4 46.9/49.0 54.5/41.629.1/36.5 (g/mil) Elmendorf Tear¹ 8.4/9.0 8.5/7.4 15.2/15.9 14.0/15.316.3/12.7 10.5/14.6 (grams) Young's Modulus¹ 81.9/82.5 60.6/63.261.0/78.9 61.0/78.9 66.4/66.6 53.3/75.2 (psi × 1000) Tear Resistance412/459 538/491 497/481 515/662 423/662 396/359 (Graves Tear)¹ (g/mil)Tear Propagation 5.5/8.2 4.3/5.2 6.4/8.5 6.5/8.4 7.5/7.6 8.4/8.3(Trouser Tear)¹ (g/mil) Instrumented Impact 8.5 9.2 18.3 9.3 7.0 6.8Strength² (lb_(f)) Total Free Shrink (%) 23 29 28 26 23 29 measured at200° F. Haze² (%) 2.3 3.1 3.0 2.5 3.3 3.6 Gloss² (%) 85.0 82.0 87.4 87.081.0 84.0 Clarity² (%) 86.2 82.0 79.7 87.3 80.0 82.6 ¹measured at 73° F.MD/TD ²measured at 73° F. ³Comparative examples 1-3 were made using astandard annular plate die, e.g., as described in U.S. Pat. No.5,076,776; the resin types indicated in the table reflect the resinsused in the single, relatively thick core layer of these comparativefilms. ⁴Values are derived from average of 8 samples ⁵Values are derivedfrom average of 5 samples

TABLE 2 Examples Test 7³ 8 9 10 11 12 Resin 1 in microlayer LLDPE-1LLDPE-2 + LLDPE-3 + VLDPE-5 + VLDPE-5 LLDPE-1 + VLDPE-1 VLDPE-4 LLDPE-1VLDPE-2 Resin 2 in microlayer MDPE-2 + LLDPE-2 LLDPE-3 LLDPE-1 LLDPE-1 +LLDPE-1 + LLDPE-1 MDPE-2 MDPE-2 Film Thickness (mils) 0.3 0.3 0.3 0.30.3 0.3 Tensile Strength at 18.5/23.6 19.7/18.4 15.9/17.3 21.0/21.320.2/22.0 18.9/19.7 yield¹ (psi × 1000) Tensile Elongation at 100/98 120/100  93/110 120/83  110/80  100/100 yield¹ (%) Elmendorf Tear¹41.1/33.6 32.2/33.6 45.0/28.6 53.2/44.4 46.3/42.1 49.8/50.9 (g/mil)Elmendorf Tear¹ 15.3/12.6 11.3/12.4 13.4/8.6  17.4/14.3 16.9/15.719.1/19.3 (grams) Young's Modulus¹ 68.1/75.6 57.6/61.7 61.4/56.555.0/74.0 62.1/68.6 61.4/66.2 (psi × 1000) Tear Resistance 443/420366/493 452/362 362/314 431/476 516/477 (Graves Tear)¹ (g/mil) TearPropagation 6.9/5.4 8.8/8.5 20.6/8.4   9.8/11.6 7.8/7.9 6.9/6.6 (TrouserTear)¹ (g/mil) Instrumented Impact 11.7 8.7 5.7 7.5 10.3 8.5 Strength²(lb_(f)) Total Free Shrink (%) 25 22 26 31 28 26 measured at 200° F.Haze² (%) 2.9 3.4 2.6 2.8 2.7 3.8 Gloss² (%) 87.0 85.0 91.0 88.0 85.081.0 Clarity² (%) 86.7 86.5 86.7 85.5 87.3 84.0 ¹measured at 73° F.MD/TD ²measured at 73° F. ³Values are derived from average of 3 samples

TABLE 3 Examples Test 13³ 14³ 15³ 16 17 18 19⁴ Resin 1 in microlayerLLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 + LLDPE-1 + Repro-1Repro-1 Resin 2 in microlayer MDPE-1 + LLDPE-1 VLDPE-1 LLDPE-1 LLDPE-1 +LLDPE-1 + LLDPE-1 + LLDPE-1 Repro-1 Repro-1 Repro-1 Film Thickness(mils) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Tensile Strength at 21.0/22.622.2/23.5 22.0/15.6 20.6/19.6 18.5/21.3 20.7/19.8 20.1/17.7 yield¹ (psi× 1000) Tensile Elongation at 73/84 91/76 86/84  94/100  98/100  96/120 93/105 yield¹ (%) Elmendorf Tear¹ 25.4/30.9 15.0/13.5 34.4/35.925.9/22.3 33.1/29.5 28.3/28.9 18.7/18.3 (g/mil) Elmendorf Tear¹ 8.3/10.6 4.9/4.5 11.5/11.7 6.8/6.0 11.2/10.0 10.4/11.5 6.5/6.6 (grams)Young's Modulus¹ 70.9/90.1 65.3/83.0 73.5/68.6 60.6/63.2 62.5/75.171.0/69.3 65.7/62.2 (psi × 1000) Tear Resistance 830/634 569/511 335/378538/491 333/371 206/334 437/536 (Graves Tear)¹ (g/mil) Tear Propagation5.7/9.1 8.8/7.4 7.2/6.2 4.3/5.2 6.0/7.4 9.8/8.5 5.9/7.9 (Trouser Tear)¹(g/mil) Instrumented Impact 8.3 9.2 7.6 9.2 9.6 9.5 9.3 Strength²(lb_(f)) Total Free Shrink (%) 22 25 27 29 18 18 32 measured at 200° F.Haze² (%) 3.1 2.1 3.7 3.1 82.8 82.6 4.0 Gloss² (%) 83.0 85.0 85.0 82.082.0 82.0 81.0 Clarity² (%) 86.7 84.5 86.8 82.0 3.6 4.1 72.9 ¹measuredat 73° F. MD/TD ²measured at 73° F. ³Orientation ratio = 6 × 6 ⁴Valuesare derived from an average of 2 samples

TABLE 4 Examples Test 20 21 22³ 23 24 25 Resin 1 in microlayer LLDPE-1 +LLDPE-1 VLDPE-2 VLDPE-3 EVA-3 VLDPE-1 Repro-2 Resin 2 in microlayerLLDPE-1 + VLDPE-1 SBS-2 LLDPE-1 MDPE-2 LLDPE-2 Repro-2 Film Thickness(mils) 0.3 0.3 0.3 0.3 0.3 0.3 Tensile Strength at 17.5/13.8 17.3/17.515.0/13.2 15.7/14.0 16.4/17.8 19.9/18.2 yield¹ (psi × 1000) TensileElongation at 79/86 93/95 75/86 95/71 120/93  100/110 yield¹ (%)Elmendorf Tear¹ 16.5/17.0 41.4/45.7 14.9/22.4 27.5/25.6 13.3/15.023.8/28.3 (g/mil) Elmendorf Tear¹ 5.7/5.9 14.0/15.3 5.5/8.7 9.6/8.94.7/5.7 8.3/9.5 (grams) Young's Modulus¹ 72.4/71.3 65.5/62.5 107.0/97.5 47.8/58.7 70.7/89.8 58.5/55.4 (psi × 1000) Tear Resistance 414/410382/328 264/331 399/369 465/381 397/389 (Graves Tear)¹ (g/mil) TearPropagation  5.6/10.5 8.9/6.9 4.9/5.9 7.4/6.2 6.3/7.4  8.7/10.0 (TrouserTear)¹ (g/mil) Instrumented Impact 7.4 8.5 4.3 7.7 7.0 8.1 Strength²(lb_(f)) Total Free Shrink (%) 22 26 29 29 23 27 measured at 200° F.Haze² (%) 2.6 3.5 3.3 3.7 3.6 3.6 Gloss² (%) 88.0 82.0 88.0 82.0 85.084.0 Clarity² (%) 74.6 86.9 85.5 83.0 85.0 82.5 ¹measured at 73° F.MD/TD ²measured at 73° F. ³Orientation ratio = 6 × 6

Example 37

In this example, the films of the Examples 1-25 were subjected to anautomated shrink-wrap packaging test. Wooden test boxes, each having thedimension 10″×7″×2″, were conveyed through a Shanklin OMNI SLRSautomated wrapping and sealing machine, wherein each box wasautomatically wrapped and heat-sealed within an enclosure formed by eachof the films of Examples 1-25. The machine effected wrapping bydirecting the film at a transverse angle to the direction of boxmovement, then center-folding and changing the direction of film travelso that a moving, center-folded envelopment of each box took place. Themachine then sealed closed the open longitudinal edge in the vicinity ofeach box to effect a “side seal,” then made transverse seals (“endseals”) upstream and downstream of each box to complete the enclosure.

Each of the enclosed boxes was then conveyed from the OMNI SLRSwrapping/sealing machine and into a Shanklin GT-71 shrink tunnel,wherein heated air was directed against the enclosed boxes, causing thefilm to shrink tightly and uniformly around the boxes.

The settings for the Shanklin OMNI SLRS wrapping/sealing machine were:

-   -   i. Side seal temperature=350-400° F.    -   ii. End seal temperature=350-400° F.    -   iii. Speed=40 fpm (“feet per minute”)

The settings for shrink tunnel Shanklin GT-71

-   -   i. Tunnel temperatures=250° F., 275° F., 300° F., 325° F., 350°        F.    -   ii. Tunnel speed=40 fpm, 70 fpm, 100 fpm

For each of the films in Examples 1-25, the test boxes were wrapped andsealed with films using the Shanklin OMNI SLRS machine at the givensettings. The wrapped boxes were then passed through the shrink tunnelat 250° F. at 40 fpm. A total of 10 wrapped boxes were passed throughthe tunnel at this temperature and speed. Maintaining the temperature,another 10 wrapped boxes were run through the tunnel 70 fpm, and 10 moreboxes at 100 fpm. The whole process was repeated at higher shrink tunneltemperature at 25° F. interval until maximum temperature of 350° F. wasreached.

In this manner, 150 packages were made for each of the films of Examples1-25, which were then subjected to the following evaluations

-   -   1. Burn outs—the total number of packages in which the film        melted and opened due to excessive heat (usually on top),        wherein a hole size larger than a dime resulted.    -   2. Scorches—the total number of areas in each of the packages        wherein the film turned white (also called ghosting) generally        due to thin film areas after the shrinking process exposed to        high heat.    -   3. Seal failures—the total number of packages with seal breaks        having a length or diameter greater than ⅛ inch.

The results are summarized in Table 5-8.

TABLE 5 Examples Test 1^(1,2) 2¹ 3^(1,3) 4 5 6 Resin 1 in microlayerLLDPE-1 + LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 VLDPE-3 Resin 2 in microlayerMDPE-1 MDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 Repro-1 MDPE-2 FilmThickness (mils) 0.3 0.3 0.6 0.3 0.3 0.3 Total number of burn 13 2 5 3 70 outs Total number of 27 22 3 0 0 2 scorches Total number of seal 2 010 0 0 23 failures ¹Comparative examples 1-3 were made using a standardannular plate die, e.g., as described in U.S. Pat. No. 5,076,776; theresin types indicated in the table reflect the resins used in thesingle, relatively thick core layer of these comparative films. ²Valuesare derived from an average of 6 samples ³Values are derived from anaverage of 3 samples

TABLE 6 Examples Test 7 8 9 10 11 12 Resin 1 in microlayer LLDPE-1LLDPE-2 + LLDPE-3 + VLDPE-5 + VLDPE-5 LLDPE-1 + VLDPE-1 VLDPE-4 LLDPE-1VLDPE-2 Resin 2 in microlayer MDPE-2 + LLDPE-2 LLDPE-3 LLDPE-1 LLDPE-1 +LLDPE-1 + LLDPE-1 MDPE-2 MDPE-2 Film Thickness (mils) 0.3 0.3 0.3 0.30.3 0.3 Total number of burn 1 12 3 1 1 4 outs Total number of 22 44 6558 57 56 scorches Total number of seal 6 0 0 0 0 0 failures

TABLE 7 Examples Test 13 14 15 16 17 18 19 Resin 1 in microlayer LLDPE-1LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 + LLDPE-1 + Repro-1 Repro-1Resin 2 in microlayer MDPE-1 + LLDPE-1 VLDPE-1 LLDPE-1 LLDPE-1 +LLDPE-1 + LLDPE-1 + LLDPE-1 Repro-1 Repro-1 Repro-1 Film Thickness(mils) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Total number of burn 3 5 9 1 1 11 8outs Total number of 28 0 12 0 39 54 0 scorches Total number of seal 0 00 0 0 0 0 failures

TABLE 8 Examples Test 20 21 22 23 24 25 Resin 1 in microlayer LLDPE-1 +LLDPE-1 VLDPE-2 VLDPE-3 EVA-3 VLDPE-1 Repro-2 Resin 2 in microlayerLLDPE-1 + VLDPE-1 SBS-2 LLDPE-1 MDPE-2 LLDPE-2 Repro-2 Film Thickness(mils) 0.3 0.3 0.3 0.3 0.3 0.3 Total number of burn 15 7 15 4 0 19 outsTotal number of 0 49 35 42 26 37 scorches Total number of seal 0 0 0 0 50 failures

The foregoing results indicate that heat-shrinkable films in accordancewith the present invention have sufficient heat-resistance and toughnessto withstand the rigors of commercial shrink film packaging equipment.

Example 38

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3-27: LLDPE-1 (2.0% of total thickness of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 39

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3-27: 50% LLDPE-1+50% Repro-1 (2.0% of total thickness of    layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 40

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3-27: LLDPE-4 (2.0% of total thickness of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 41

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3-27: LLDPE-2 (2.0% of total thickness of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 42

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3-27: 50% LLDPE-1+50% Repro-3 (2.0% of total thickness of    layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 43

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that thetape was not cross-linked; the film had the following twenty nine-layerstructure with a total film thickness of 0.60 mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3-27: LLDPE-1 (2.0% of total thickness of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 44

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that thetape was cross-linked at between 45 and 90 kGy; the film had thefollowing twenty nine-layer structure with a total film thickness of0.60 mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3-27: LLDPE-1 (2.0% of total thickness of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 45

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (7.1% of    total thickness of layers 1-29);-   Layers 3, 6, 9, 12, 15, 18, 21, 24, 27:    -   LLDPE-1 (2.78% of total thickness of layers 1-29);-   Layers 4, 7, 10, 13, 16, 19, 22, 25:    -   LLDPE-1 (2.24% of total thickness of layers 1-29);-   Layers 5, 8, 11, 14, 17, 20, 23, 26:    -   Repro-1 (0.89% of total thickness of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (17.9% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 46

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (7.1% of    total thickness of layers 1-29);-   Layers 3, 6, 9, 12, 15, 18, 21, 24, 27:    -   LLDPE-1 (2.78% of total thickness of layers 1-29);-   Layers 4, 7, 10, 13, 16, 19, 22, 25:    -   LLDPE-1 (2.24% of total thickness of layers 1-29);-   Layers 5, 8, 11, 14, 17, 20, 23, 26:    -   50% LLDPE-1+50% Repro-1 (0.89% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (17.9% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 47

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (7.1% of    total thickness of layers 1-29);-   Layers 3, 6, 9, 12, 15, 18, 21, 24, 27:    -   LLDPE-1 (2.38% of total thickness of layers 1-29);-   Layers 4, 7, 10, 13, 16, 19, 22, 25:    -   50% LLDPE-1+50% Repro-1 (1.79% of total thickness of layers        1-29);-   Layers 5, 8, 11, 14, 17, 20, 23, 26:    -   50% LLDPE-1+50% Repro-1 (1.79% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (17.9% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 48

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   60% LLDPE-1+40% MDPE-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 49

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   55.6% LLDPE-1+27.6% MDPE-1+16.8% EVA-1 (2.08% of total thickness        of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 50 Comparative

A multilayer film in accordance with the present invention was made bythe process described above for Comparative Example 1, and had thefollowing five-layer structure with total film thickness of 0.52 mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 3: LLDPE-1 (50.0% of total thickness of layers 1-29);-   Layer 4: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 5: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 51

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.50mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   50% LLDPE-1+50% Repro-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 52 Comparative

A multilayer film in accordance with the present invention was made bythe process described above for Comparative Example 1, and had thefollowing five-layer structure with total film thickness of 0.75 mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-5);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-5);-   Layer 3: LLDPE-1 (50.0% of total thickness of layers 1-5);-   Layer 4: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-5);-   Layer 5: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-5)

Example 53

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 0.75mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   50% LLDPE-1+50% Repro-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 54 Comparative

A multilayer film in accordance with the present invention was made bythe process described above for Comparative Example 1, and had thefollowing five-layer structure with total film thickness of 1.00 mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-5);-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-5);-   Layer 3: LLDPE-1 (55.0% of total thickness of layers 1-5);-   Layer 4: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-5);-   Layer 5: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-5)

Example 55

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 1.00mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-29)-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (2.12% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   50% LLDPE-1+50% Repro-1 (2.29% of total thickness of layers        1-29);-   Layer 28: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layer 29: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2    (7.9% of total thickness of layers 1-29)

Example 56

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 1.00mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-29);-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.48% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   60% LLDPE-1+40% MDPE-1 (2.98% of total thickness of layers        1-29);-   Layer 28: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layer 29: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2    (7.9% of total thickness of layers 1-29)

Example 57

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, and had thefollowing twenty nine-layer structure with total film thickness of 1.00mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-29);-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (2.12% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   55.6% LLDPE-1+27.6% MDPE-1+16.8% EVA-1 (2.29% of total thickness        of layers 1-29);-   Layer 28: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layer 29: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2    (7.9% of total thickness of layers 1-29)

Example 58 Comparative

A multilayer film in accordance with the present invention was made bythe process described above for Comparative Example 1, except that thefilm was oriented at a ratio of 4×4; the film had the followingthree-layer structure with a total film thickness of 2.00 mils:

-   Layer 1: 50.0% LLDPE-1+25.0% MDPE-1+17.0% EVA-1+8.0% MB-5 (17.5% of    total thickness of layers 1-3);-   Layer 2: LLDPE-1 (65.0% of total thickness of layers 1-3);-   Layer 3: 50.0% LLDPE-1+25.0% MDPE-1+17.0% EVA-1+8.0% MB-5 (17.5% of    total thickness of layers 1-3)

Example 59 Comparative

A multilayer film in accordance with the present invention was made bythe process described above for Comparative Example 1, except that thefilm was oriented at a ratio of 3.5×3.5; the film had the followingfive-layer structure with total film thickness of 2.00 mils:

-   Layer 1: 50.0% LLDPE-1+40.0% EVA-1+10.0% MB-6 (20.0% of total    thickness of layers 1-5);-   Layer 2: 80% VLDPE-1+20% EVA-1 (25.0% of total thickness of layers    1-5);-   Layer 3: SBS-2 (10.0% of total thickness of layers 1-5);-   Layer 4: 80% VLDPE-1+20% EVA-1 (25.0% of total thickness of layers    1-5);-   Layer 5: 50.0% LLDPE-1+40.0% EVA-1+10.0% MB-6 (20.0% of total    thickness of layers 1-5)

Example 60

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that thefilm was oriented at a ratio of 4×4; the film had the following twentynine-layer structure with total film thickness of 2.00 mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-29);-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (2.12% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   50% LLDPE-1+50% Repro-1 (2.29% of total thickness of layers        1-29);-   Layer 28: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layer 29: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2    (7.9% of total thickness of layers 1-29)

Example 61

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that thefilm was oriented at a ratio of 4×4; the film had the following twentynine-layer structure with total film thickness of 2.00 mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-29);-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.48% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   60% LLDPE-1+40% MDPE-1 (2.98% of total thickness of layers        1-29);-   Layer 28: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layer 29: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2    (7.9% of total thickness of layers 1-29)

Example 62

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 4, except that thefilm was oriented at a ratio of 4×4; the film had the following twentynine-layer structure with total film thickness of 2.00 mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-29);-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (2.12% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   55.6% LLDPE-1+27.6% MDPE-1+16.8% EVA-1 (2.29% of total thickness        of layers 1-29);-   Layer 28: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-29);-   Layer 29: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2    (7.9% of total thickness of layers 1-29)

Example 63

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   50% LLDPE-1+50% Repro-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 64

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.60mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   60% LLDPE-1+40% MDPE-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 65

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.59mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   55.6% LLDPE-1+27.6% MDPE-1+16.8% EVA-1 (2.08% of total thickness        of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 66

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.69mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   50% LLDPE-1+50% Repro-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 67

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.71mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   60% LLDPE-1+40% MDPE-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 68

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.76mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   55.6% LLDPE-1+27.6% MDPE-1+16.8% EVA-1 (2.08% of total thickness        of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 69

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.68mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   50% LLDPE-1+50% Repro-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 70

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.70mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   60% LLDPE-1+40% MDPE-1 (2.08% of total thickness of layers        1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 71

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except stretch oriented as abubble at an orientation ratio of 6×6 (TD×LD). The film had thefollowing twenty nine-layer structure with total film thickness of 0.66mils:

-   Layer 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layer 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layers 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27:    -   LLDPE-1 (1.92% of total thickness of layers 1-29);-   Layers 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26    -   55.6% LLDPE-1+27.6% MDPE-1+16.8% EVA-1 (2.08% of total thickness        of layers 1-29);-   Layer 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (12.5% of    total thickness of layers 1-29);-   Layer 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 72

A multilayer film in accordance with the present invention was made bythe process described above for Example 4, except that the film was asshown in FIG. 8, with a microlayer section on the outside of the blowntube and bulk layers on the inside of the tube. The blown tube wascollapsed and welded together such that the inner bulk layers adhered toone another. The resultant shrink film had a microlayer section on bothouter surfaces (skins) of the film, with five bulk layers in the centerto form the core of the film, for a total of fifty-five (55) layers anda total film thickness of 1.06 mils.

-   Layer 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25:    -   80.0% LLDPE-1+20.0% MB-2 (8.14% of total thickness of layers        1-55);-   Layer 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24:    -   LLDPE-1 (8.14% of total thickness of layers 1-55);-   Layer 26: 80.0% LLDPE-1+20.0% MB-3 (5.45% of total thickness of    layers 1-55);-   Layer 27: LLDPE-1 (25.55% of total thickness of layers 1-55);-   Layer 28: EVA-4 (5.45% of total thickness of layers 1-55);-   Layer 29: LLDPE-1 (25.55% of total thickness of layers 1-55);-   Layer 30: 80.0% LLDPE-1+20.0% MB-3 (5.45% of total thickness of    layers 1-55);-   Layer 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54:    -   LLDPE-1 (8.14% of total thickness of layers 1-55);-   Layer 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55:    -   80.0% LLDPE-1+20.0% MB-2 (8.14% of total thickness of layers        1-55)

Example 73 Comparative

A multilayer film in accordance with the present invention was made bythe process described above for Comparative Example 1, and had thefollowing five-layer structure with total film thickness of 1.25 mils:

-   Layer 1: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-5);-   Layer 2: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-5);-   Layer 3: LLDPE-1 (55.0% of total thickness of layers 1-5);-   Layer 4: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-3    (14.6% of total thickness of layers 1-5);-   Layer 5: 50.04% LLDPE-1+24.84% MDPE-1+15.12% EVA-1+10.00% MB-2 (7.9%    of total thickness of layers 1-5)

Example 74

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 72, and had thefollowing fifty five-layer structure with total film thickness of 1.20mils:

-   Layer 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25:    -   80.0% LLDPE-1+20.0% MB-2 (8.1% of total thickness of layers        1-55);-   Layer 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24:    -   60% MDPE-1+40% EVA-1 (6.52% of total thickness of layers 1-55);-   Layer 26: 80.0% LLDPE-1+20.0% MB-3 (6.52% of total thickness of    layers 1-55);-   Layer 27: LLDPE-1 (25.59% of total thickness of layers 1-55);-   Layer 28: EVA-4 (6.52% of total thickness of layers 1-55);-   Layer 29: LLDPE-1 (25.59% of total thickness of layers 1-55);-   Layer 30: 80.0% LLDPE-1+20.0% MB-3 (6.52% of total thickness of    layers 1-55);-   Layer 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54:    -   60% MDPE-1+40% EVA-1 (6.52% of total thickness of layers 1-55);-   Layer 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55:    -   80.0% LLDPE-1+20.0% MB-2 (8.1% of total thickness of layers        1-55)

Example 75

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 72, and had thefollowing fifty five-layer structure with total film thickness of 1.26mils:

-   Layer 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25:    -   80.0% LLDPE-1+20.0% MB-2 (8.1% of total thickness of layers        1-55);-   Layer 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24:    -   LLDPE-1 (6.52% of total thickness of layers 1-55);-   Layer 26: 80.0% LLDPE-1+20.0% MB-3 (6.52% of total thickness of    layers 1-55);-   Layer 27: LLDPE-1 (25.59% of total thickness of layers 1-55);-   Layer 28: EVA-4 (6.52% of total thickness of layers 1-55);-   Layer 29: LLDPE-1 (25.59% of total thickness of layers 1-55);-   Layer 30: 80.0% LLDPE-1+20.0% MB-3 (6.52% of total thickness of    layers 1-55);-   Layer 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54:    -   LLDPE-1 (6.52% of total thickness of layers 1-55);-   Layer 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55:    -   80.0% LLDPE-1+20.0% MB-2 (8.1% of total thickness of layers        1-55)

Example 76

A multilayer film in accordance with the present invention was made bythe process described above for Inventive Example 72, and had thefollowing fifty five-layer structure with total film thickness of 1.34mils:

-   Layer 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25:    -   80.0% LLDPE-1+20.0% MB-2 (8.1% of total thickness of layers        1-55);-   Layer 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24:    -   60.0% MDPE-1+40.0% EVA-1 (6.52% of total thickness of layers        1-55);-   Layer 26: LLDPE-1 (6.52% of total thickness of layers 1-55);-   Layer 27: LLDPE-1 (25.59% of total thickness of layers 1-55);-   Layer 28: EVA-4 (6.52% of total thickness of layers 1-55);-   Layer 29: LLDPE-1 (25.59% of total thickness of layers 1-55);-   Layer 30: LLDPE-1 (6.52% of total thickness of layers 1-55);-   Layer 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54:    -   60.0% MDPE-1+40.0% EVA-1 (6.52% of total thickness of layers        1-55);-   Layer 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55:    -   80.0% LLDPE-1+20.0% MB-2 (8.1% of total thickness of layers        1-55)

In the following Examples 77-81, the described films were attempted tobe made in accordance with Example 4, except that processing problemsprevented the films from being oriented.

Example 77

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (16.05% of    total thickness of layers 1-29);-   Layers 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (8.90% of    total thickness of layers 1-29);-   Layers 3, 6, 9, 12, 15, 18, 21, 24, 27:    -   LLDPE-1 (2.78% of total thickness of layers 1-29)-   Layers 4, 7, 10, 13, 16, 19, 22, 25:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 5, 8, 11, 14, 17, 20, 23, 26:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (8.90% of    total thickness of layers 1-29);-   Layers 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (16.05%    of total thickness of layers 1-29)

Example 78

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29);-   Layers 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (7.02% of    total thickness of layers 1-29);-   Layers 3, 6, 9, 12, 15, 18, 21, 24, 27:    -   LLDPE-1 (2.78% of total thickness of layers 1-29)-   Layers 4, 7, 10, 13, 16, 19, 22, 25:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 5, 8, 11, 14, 17, 20, 23, 26:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (19.3% of    total thickness of layers 1-29);-   Layers 29: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (12.5% of    total thickness of layers 1-29)

Example 79

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1: 43.03% LLDPE-1+21.36% MDPE-1+13.00% EVA-1+22.6% MB-2    (16.07% of total thickness of layers 1-29);-   Layers 2: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-3 (8.93% of    total thickness of layers 1-29);-   Layers 3, 6, 9, 12, 15, 18, 21, 24, 27:    -   LLDPE-1 (2.78% of total thickness of layers 1-29)-   Layers 4, 7, 10, 13, 16, 19, 22, 25:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 5, 8, 11, 14, 17, 20, 23, 26:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 28: 47.8% LLDPE-1+23.7% MDPE-1+14.5% EVA-1+14% MB-2 (8.93% of    total thickness of layers 1-29);-   Layers 29: 43.03% LLDPE-1+21.36% MDPE-1+13.00% EVA-1+22.6% MB-2    (16.07% of total thickness of layers 1-29)

Example 80

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layers 1: 43.03% LLDPE-1+21.36% MDPE-1+13.00% EVA-1+22.6% MB-2    (14.29% of total thickness of layers 1-29);-   Layers 2: 43.03% LLDPE-1+21.36% MDPE-1+13.00% EVA-1+22.6% MB-2    (7.14% of total thickness of layers 1-29);-   Layers 3, 6, 9, 12, 15, 18, 21, 24, 27:    -   LLDPE-1 (2.78% of total thickness of layers 1-29)-   Layers 4, 7, 10, 13, 16, 19, 22, 25:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 5, 8, 11, 14, 17, 20, 23, 26:    -   LLDPE-1 (1.56% of total thickness of layers 1-29)-   Layers 28: 43.03% LLDPE-1+21.36% MDPE-1+13.00% EVA-1+22.6% MB-2    (14.29% of total thickness of layers 1-29);-   Layers 29: 43.03% LLDPE-1+21.36% MDPE-1+13.00% EVA-1+22.6% MB-2    (14.29% of total thickness of layers 1-29)

Example 81

A multilayer film was coextruded through an annular 29-layer die, andhad the following structure:

-   Layer 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25:    -   80.0% LLDPE-1+20.0% MB-2 (6.64% of total thickness of layers        1-55);-   Layer 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24:    -   60.0% MDPE-1+40.0% EVA-1 (8.30% of total thickness of layers        1-55);-   Layer 26: LLDPE-1 (6.64% of total thickness of layers 1-55);-   Layer 27: LLDPE-1 (25.23% of total thickness of layers 1-55);-   Layer 28: EVA-4 (6.47% of total thickness of layers 1-29);-   Layer 29: LLDPE-1 (25.23% of total thickness of layers 1-55);-   Layer 30: LLDPE-1 (6.64% of total thickness of layers 1-55);-   Layer 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54:    -   60.0% MDPE-1+40.0% EVA-1 (8.30% of total thickness of layers        1-55);-   Layer 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55:    -   80.0% LLDPE-1+20.0% MB-2 (6.64% of total thickness of layers        1-55)

TABLE 9 Examples Test 3^(3,4) 38 39 40 41 42 Resin in microlayer 1LLDPE-1 LLDPE-1 LLDPE-1 + LLDPE-4 LLDPE-2 LLDPE-1 + Repro-1 Repro-2Resin(s) in microlayer LLDPE-1 LLDPE-1 + LLDPE-4 LLDPE-2 LLDPE-1 + 2Repro-1 Repro-2 Film Thickness (mils) 0.6 0.6 0.6 0.6 0.6 0.6 TensileStrength at 17.8/18.9 20.3/18.7 20.4/19.5 19.7/20.7 17.9/16.8 16.4/14.9yield¹ (psi × 1000) Tensile Elongation at  86/120 140/120 115/110 94/78120/130 110/100 yield¹ (%) Elmendorf 23.7/24.8 35.2/31.5 18.3/17.514.9/13.3 19.0/23.2 13.5/14.0 Tear¹ (g/mil) Elmendorf 14.2/15.022.7/20.2 11.0/10.6 8.4/7.7 12.6/15.5 8.5/8.9 Tear¹ (grams) Young'sModulus¹ 60.4/62.2 57.0/62.9 63.9/67.1 64.8/71.4 49.4/60.2 70.4/68.3(psi × 1000) Tear Resistance 492/478 530/509 505/490 602/595 429/485449/495 (Graves Tear)¹ (g/mil) Tear Propagation 6.5/8.7 10.1/8.9 8.0/7.9 16.1/18.4  9.3/13.9  7.8/10.4 (Trouser Tear)¹ (g/mil)Instrumented Impact 18.0 16.7 16.6 12.5 15.9 12.5 Strength² (lb_(f))Instrumented Impact 29.0 26.5 28.4 20.9 24.8 20.5 Strength² (lb_(f)/mil)Total Free Shrink 29 30 31 33 34 27 measured at 200° F. Clarity² (%)79.1 74.1 73.4 82.2 81.4 3.0 Gloss² (%) 88 81 85 88 90 63 Haze² (%) 3.04.9 3.6 3.3 2.7 11.9 ¹measured at 73° F. MD/TD ²measured at 73° F.³Comparative example 3 was made using a standard annular plate die,e.g., as described in U.S. Pat. No. 5,076,776; the resin types indicatedin the table reflect the resins used in the single, relatively thickcore layer of these comparative films. ⁴Values are derived form anaverage of 6 samples.

TABLE 10 Examples Test 43 44 45 46 47 48 49 Resin in microlayer 1LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 Resin(s) inmicrolayer LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 + LLDPE-1 + LLDPE-1 +2 Repro-1 MDPE-1 MDPE-1 + EVA-1 Resin(s) in microlayer — — Repro-1LLDPE-1 + LLDPE-1 + — — 3 Repro-1 Repro-1 Film Thickness (mils) 0.6 0.60.6 0.6 0.6 0.6 0.6 Tensile Strength at 17.5/14.3 20.8/25.1 20.8/19.120.5/19.2 19.7/18.3 19.5/16.7 17.4/15.4 yield¹ (psi × 1000) TensileElongation at 150/180 95/62 130/97  130/120 130/110 120/120 120/130yield¹ (%) Elmendorf 19.5/24.1 10.9/7.8  58.7/78.7 53.7/47.5 46.7/38.946.9/41.8 48.3/94.3 Tear¹ (g/mil) Elmendorf 13.3/17.0 6.0/4.4 40.9/52.535.8/32.2 30.6/25.6 30.1/26.6 32.3/66.2 Tear¹ (grams) Young's Modulus¹55.9/61.3 62.7/64.5 60.3/69.2 58.1/60.8 59.4/60.7 63.4/61.4 58.3/58.0(psi × 1000) Tear Resistance 530/615 398/326 571/530 612/462 602/599446/426 357/432 (Graves Tear)¹ (g/mil) Tear Propagation 16.5/30.97.0/4.9 7.9/9.9 9.2/9.5 9.3/9.1 6.7/8.3 6.5/7.4 (Trouser Tear)¹ (g/mil)Instrumented Impact 13.1 21.4 19.1 18.9 18.7 19.3 16.7 Strength²(lb_(f)) Instrumented Impact 18.2 39.0 28.6 28.1 27.5 30.3 23.7Strength² (lb_(f)/mil) Total Free Shrink 30 26 33 33 33 27 31 measuredat 200° F. Clarity² (%) 71.3 85.0 73.1 75 73.2 79.7 79.0 Gloss² (%) 7591 84 85 82 83 83 Haze² (%) 5.4 2.7 4.4 4.2 4.4 3.9 3.9 ¹measured at 73°F. MD/TD ²measured at 73° F.

TABLE 11 Examples Test 50³ 51 52³ 53 54³ 55 56 Resin 1 in microlayerLLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 Resin 2 inmicrolayer LLDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 + Repro-1 Repro-1Repro-1 MDPE-1 Film Thickness (mils) 0.52 0.5 0.75 0.75 1.0 1.0 1.0Tensile Strength at 18.0/18.3 19.9/20.3 18.2/18.9 19.3/20.0 18.7/18.818.1/16.3 17.9/16.7 yield¹ (psi × 1000) Tensile Elongation at  75/100120/91   91/120 110/110 140/140 140/140 160/160 yield¹ (%) Elmendorf17.3/22.3 47.8/32.9 22.9/22.7 44.5/36.8 32.6/28.9 34.9/44.9 67.6/60.9Tear¹ (g/mil) Elmendorf  9.3/11.8 29.4/19.7 16.7/16.7 38.8/32.335.9/31.9 39.2/51.5 97.1/85.3 Tear¹ (grams) Young's Modulus¹ 63.3/60.553.5/56.8 64.4/65.2 56.5/62.6 58.7/66.4 51.0/61.0 59.6/60.2 (psi × 1000)Tear Resistance 335/450 297/296 376/421 407/375 N/A 337/417 460/522(Graves Tear)¹ (g/mil) Tear Propagation 5.2/7.5 5.8/4.3 6.3/8.2 7.5/5.89.7/9.7  8.5/13.2 10.4/9.3  (Trouser Tear)¹ (g/mil) Instrumented Impact16.6 20.8 23.2 27.4 31.6 29.9 40.1 Strength² (lb_(f)) InstrumentedImpact 31.0 36.6 31.7 33.4 28.5 26.8 28.3 Strength² (lb_(f)/mil) TotalFree Shrink 31 36 31 33 29 29 30 measured at 200° F. Clarity² (%) 76.476.5 79.6 72.3 80.3 69.9 67.8 Gloss² (%) 87 87 90 84 86 78 74 Haze² (%)3.9 3.5 3.0 4.5 2.6 4.9 5.1 ¹measured at 73° F. MD/TD ²measured at 73°F. ³Comparative examples 50, 52 and 54 were made using a standardannular plate die, e.g., as described in U.S. Pat. No. 5,076,776; theresin types indicated in the table reflect the resins used in thesingle, relatively thick core layer of these comparative films.

TABLE 12 Examples Test 57 58³ 59³ 60 61 62 63⁴ Resin 1 in microlayerLLDPE-1 LLDPE-1 SBS-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 Resin 2 inmicrolayer LLDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 + MDPE-1 +Repro-1 MDPE-1 MDPE-1 + Repro-1 EVA-1 EVA-1 Film Thickness (mils) 1.02.0 2.0 2.0 2.0 2.0 0.6 Tensile Strength at 17.3/16.2 15.1/13.711.1/14.3 14.0/15.9 14.9/15.4 13.0/14.0 20.1/20.7 yield¹ (psi × 1000)Tensile Elongation at 140/130 160/190 200/190 200/170 210/190 180/20083/91 yield¹ (%) Elmendorf 48.5/48.7 29.2/40.4 62.9/40.6 59.8/68.984.8/70.1 71.2/90.9  9.8/13.6 Tear¹ (g/mil) Elmendorf 59.9/59.063.6/88.5 124.6/80.1  114.3/131.3 155.0/127.2 129.2/159.3 5.6/7.8 Tear¹(grams) Young's Modulus¹ 52.5/60.5 55.4/56.8 36.3/36.9 49.5/55.458.5/57.1 53.4/53.0 67.4/71.6 (psi × 1000) Tear Resistance 456/485 —350/388 469/437 498/439 494/472 350/404 (Graves Tear)¹ (g/mil) TearPropagation  9.8/11.5 — 17.9/16.8 21.0/16.0 36.3/34.2 21.5/18.08.98/9.99 (Trouser Tear)¹ (g/mil) Instrumented Impact 32.8 46.0 35.537.5 40.5 37.3 20.7 Strength² (lb_(f)) Instrumented Impact 26.0 21.217.5 19.8 22.3 19.2 31.8 Strength² (lb_(f)/mil) Total Free Shrink 29 2851 28 28 29 26 measured at 200° F. Clarity² (%) 75.7 61.6 67.7 60.5 65.764.0 79.5 Gloss² (%) 79 84 88 73 72 68 90 Haze² (%) 3.8 5.1 3.5 5.7 5.56.7 3.14 ¹measured at 73° F. MD/TD ²measured at 73° F. ³Comparativeexamples 58 and 59 were made using a standard annular plate die, e.g.,as described in U.S. Pat. No. 5,076,776; the resin types indicated inthe table reflect the resins used in the single, relatively thick corelayer of these comparative films. ⁴Orientation ratio = 6 × 6

TABLE 13 Examples Test 64³ 65³ 66³ 67³ 68³ 69³ 70³ Resin 1 in microlayerLLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 LLDPE-1 Resin 2 inmicrolayer LLDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 + LLDPE-1 +LLDPE-1 + MDPE-1 MDPE-1 + Repro-1 MDPE-1 MDPE-1 + Repro-1 MDPE-1 EVA-1EVA-1 Film Thickness (mils) 0.6 0.59 0.69 0.71 0.76 0.68 0.7 TensileStrength at 20.2/22.4 20.4/22.6 21.2/20.5 21.6/18.3 21.8/20.6 18.8/22.022.2/23.2 yield¹ (psi × 1000) Tensile Elongation at 89/90 90/88 94/99 96/120  97/110 98/85 110/96  yield¹ (%) Elmendorf 16.2/18.9 13.9/18.411.9/15.4 17.1/24.2 19.8/18.7 15.4/11.8 16.2/17.9 Tear¹ (g/mil)Elmendorf 10.1/11.6  7.9/10.4  8.3/10.3 12.9/19.2 14.2/13.3 11.2/8.3 12.1/13.7 Tear¹ (grams) Young's Modulus¹ 63.5/72.5 66.9/74.9 66.0/71.664.1/64.3 66.3/68.3 67.9/76.6 68.3/78.6 (psi × 1000) Tear Resistance442/288 427/413 401/407 515/437 428/469 357/380 460/404 (Graves Tear)¹(g/mil) Tear Propagation 9.52/9.09 8.45/9.01 6.9/6.5 7.1/6.4 6.3/8.8 9.94/10.19  8.98/11.23 (Trouser Tear)¹ (g/mil) Instrumented Impact 19.121.2 23.6 25.2 23.8 21.9 25.6 Strength² (lb_(f)) Instrumented Impact32.2 36.3 35.6 33.2 34.1 32.3 34.4 Strength² (lb_(f)/mil) Total FreeShrink 26 25 36 33 41 26 25 measured at 200° F. Clarity² (%) 84.2 80.878.6 81.7 82.8 78.8 80.5 Gloss² (%) 91 90 86.9 85.6 88.2 90 89 Haze² (%)2.83 3.07 3.35 3.26 3.23 3.37 3.72 ¹measured at 73° F. MD/TD ²measuredat 73° F. ³Orientation ratio = 6 × 6

TABLE 14 Examples Test 71⁴ 72⁵ 73³ 74⁵ 75⁵ 76⁵ Resin 1 in microlayerLLDPE-1 LLDPE-1 + LLDPE-1 LLDPE-1 + LLDPE-1 + LLDPE-1 + MB-2 MB-2 MB-2MB-2 Resin 2 in microlayer LLDPE-1 + LLDPE-1 MDPE-1 + LLDPE-1 MDPE-1 +MDPE-1 + EVA-1 EVA-1 EVA-1 Film Thickness (mils) 0.66 1.06 1.25 1.201.26 1.34 Tensile Strength at 18.7/23.6 16.9/15.2 15.3/17.9 13.6/12.616.8/17.1 18.9/17.2 yield¹ (psi × 1000) Tensile Elongation at 93/87100/120 190/170 130/130 110/120 120/120 yield¹ (%) Elmendorf 14.1/15.350.8/59.9 52.0/42.4 26.9/31.3 31.7/57.2 36.7/25.0 Tear¹ (g/mil)Elmendorf  9.6/11.0 52.1/66.9 79.4/64.8 32.7/42.0 37.3/74.6 46.7/34.9Tear¹ (grams) Young's Modulus¹ 69.3/83.4 44.3/44.2 48.3/59.0 43.7/46.044.2/46.4 46.4/45.1 (psi × 1000) Tear Resistance 361/403 293/281 481/429388/360 345/365 361/316 (Graves Tear)¹ (g/mil) Tear Propagation 9.28/10.36 5.17/6.49  9.8/12.3 8.83/8.28 6.19/6.56 5.88/6.03 (TrouserTear)¹ (g/mil) Instrumented Impact 22.5 34.0 36.2 21.3 40.4 41.2Strength² (lb_(f)) Instrumented Impact 32.7 32.0 23.5 17.5 32.1 32.3Strength² (lb_(f)/mil) Total Free Shrink 28 38 29 30 34 35 measured at200° F. Clarity² (%) 82.3 22.9 76.9 56.1 30 52.4 Gloss² (%) 91 81.0 80.075.0 90 94 Haze² (%) 3.32 6.40 4.20 6.90 5.9 6.1 ¹measured at 73° F.MD/TD ²measured at 73° F. ³Comparative examples 73 was made using astandard annular plate die, e.g., as described in U.S. Pat. No.5,076,776; the resin types indicated in the table reflect the resinsused in the single, relatively thick core layer of these comparativefilms. ⁴Orientation ratio = 6 × 6 ⁵Microlayers are placed on the outside

While the invention has been described with reference to illustrativeexamples, those skilled in the art will understand that variousmodifications may be made to the invention as described withoutdeparting from the scope of the claims which follow.

What is claimed is:
 1. A multilayer, heat-shrinkable film, comprising: a. a bulk layer; and b. a microlayer section comprising at least ten microlayers, each of said microlayers having a thickness ranging from about 0.001 to 0.015 mil, wherein: each of said microlayers and said bulk layer have a thickness, the ratio of the thickness of any of said microlayers to the thickness of said bulk layer being at least 1:2; said film is stretch-oriented at a ratio of at least 4 in at least one direction along a length or width dimension of said film; and said film has a total free shrink (ASTM D2732-03) of at least about 10% at 200° F.; and said heat-shrinkable film has an Elmendorf Tear value (ASTM D1922-06a) of at least about 30 grams/mil, as measured in at least one direction along a length or width dimension of said film.
 2. The film of claim 1, wherein said film is stretch-oriented at a ratio of at least 5 in at least one direction along a length or width dimension of said film.
 3. The film of claim 1, wherein, said film has a thickness of less than about 0.7 mil.
 4. The heat-shrinkable film of claim 1, wherein at least one of said microlayers comprises recycled polymer.
 5. The film of claim 1, wherein said microlayer section comprises a repeating sequence of layers represented by the structure: A/B, wherein, A represents a microlayer comprising one or more polymers, B represents a microlayer comprising a blend of two or more polymers, and A has a composition that is different from that of B.
 6. The film of claim 3, wherein said film has an Elmendorf Tear value (ASTM D1922-06a) of at least 10 grams, as measured in at least one direction along a length or width dimension of said film.
 7. The heat-shrinkable film of claim 4, wherein said microlayer section comprises between 1 and 50 weight percent recycled polymer, based on the total weight of the film.
 8. The film of claim 5, wherein A and B comprise one or more of ethylene/alpha-olefin copolymer, ethylene/vinyl acetate copolymer, polypropylene homopolymer or copolymer, ethylene/methacrylic acid copolymer, maleic-anhydride-grafted polyethylene, polyamide, or low density polyethylene.
 9. The heat-shrinkable film of claim 5, wherein B comprises between 1 and 50 weight percent recycled polymer, based on the total weight of the film. 